Crown Low Power Transmitters - Crown Broadcast

® 

FM30/FM100/FM250 

Broadcast Transmitter 

User's Manual 

©2005 Crown Broadcast, a division of International Radio and Electronics, Inc. 

25166 Leer Drive, Elkhart, Indiana, 46514-5425 U.S.A. 

(574) 262-8900 

i

Revision Control 

Revision 

Print Date 

Initial Release (Rev. 0; K80620–6) February 1995 

Revision 1 (K80664–4) November 1995 

Revision 2 (K80664A2) March 1996 

Revision 3 (100885–1) October 1996 

Revision 4 (100885–2) July 1997 

Revision 5 (900194-1) October 1997 

Revision 6 (130758-1) April 2000 

Revision 7 April 2002 

Revision 8 April 2005 

Important Notices 

©2005, Crown Broadcast, a division of International Radio and Electronics, Inc. 

Portions of this document were originally copyrighted by Michael P. Axman in 1991. 

All rights reserved. No part of this publication may be reproduced, transmitted, 

transcribed, stored in a retrieval system, or translated into any language in any 

form by any means without the written permission of Crown International, Inc. 

Printed in U.S.A. 

Crown attempts to provide information that is accurate, complete, and useful. 

Should you find inadequacies in the text, please send your comments to the following 

address: 

International Radio and Electronics 

25166 Leer Drive, P.O. Box 2000 

Elkhart, Indiana, 46515-2000 U.S.A. 

ii

Contents 

Section 1—Getting Acquainted ..................................... 1–1 

1.1 Your Transmitter ............................................................................................... 1–2 

1.2 Applications and Options................................................................................... 1–3 

1.2.1 Stand-Alone .................................................................................................. 1–4 

1.2.2 Backup .......................................................................................................... 1–4 

1.2.3 Booster ......................................................................................................... 1–4 

1.2.4 Exciter........................................................................................................... 1–4 

1.2.5 Translator...................................................................................................... 1–5 

1.2.6 Satellator ...................................................................................................... 1–6 

1.2.7 Nearcasting ................................................................................................... 1–6 

1.3 Transmitter/Exciter Specifications ..................................................................... 1–7 

1.4 Receiver Specifications ..................................................................................... 1–9 

1.5 Safety Considerations...................................................................................... 1–10 

1.5.1 Dangers ...................................................................................................... 1–10 

1.5.2 Warnings .................................................................................................... 1–10 

1.5.3 Cautions...................................................................................................... 1–10 

Section 2—Installation ............................................... 2–1 

2.1 Operating Environment...................................................................................... 2–2 

2.2 Power Connections ........................................................................................... 2–2 

2.2.1 AC Line Voltage Setting ................................................................................ 2–2 

2.2.2 Fuses ............................................................................................................ 2–4 

2.2.3 Battery Power ............................................................................................... 2–5 

2.3 Frequency (Channel) Selection .......................................................................... 2–5 

2.3.1 Modulation Compensator .............................................................................. 2–7 

2.4 Receiver Frequency Selection ............................................................................ 2–7 

2.5 RF Connections ............................................................................................... 2–10 

2.6 Audio Input Connections ................................................................................. 2–11 

2.7 SCA Input Connections ................................................................................... 2–12 

2.8 Composite Input Connection ........................................................................... 2–12 

2.9 Audio Monitor Connections ............................................................................. 2–13 

2.10 Pre-emphasis Selection ................................................................................... 2–13 

2.11 Program Input Fault Time-out...........................................................................2–14 

2.12 Remote I/O Connector.....................................................................................2–14 

iii

Section 3—Operation ................................................. 3–1 

3.1 Initial Power-up Procedures .............................................................................. 3–2 

3.2 Power Switches................................................................................................. 3–4 

3.2.1 DC Breaker.................................................................................................... 3–4 

3.2.2 Power Switch ................................................................................................ 3–4 

3.2.3 Carrier Switch ............................................................................................... 3–4 

3.3 Front Panel Bar-Dot Displays ............................................................................. 3–5 

3.3.1 Audio Processor Input .................................................................................. 3–5 

3.3.2 Highband and Wideband Display .................................................................. 3–5 

3.3.3 Modulation Display ....................................................................................... 3–5 

3.4 Input Gain Switches .......................................................................................... 3–6 

3.5 Processing Control ............................................................................................ 3–6 

3.6 Stereo-Mono Switch.......................................................................................... 3–6 

3.7 RF Output Control ............................................................................................. 3–7 

3.8 Digital Multimeter .............................................................................................. 3–7 

3.9 Fault Indicators ................................................................................................. 3–8 

Section 4—Principles of Operation................................. 4–1 

4.1 Part Numbering ................................................................................................. 4–2 

4.2 Audio Processor Circuit Board .......................................................................... 4–3 

4.3 Stereo Generator Circuit Board.......................................................................... 4–4 

4.4 RF Exciter Circuit Board .................................................................................... 4–6 

4.5 Metering Circuit Board ...................................................................................... 4–8 

4.6 Motherboard ..................................................................................................... 4–9 

4.7 Display Circuit Board ....................................................................................... 4–10 

4.8 Voltage Regulator Circuit Board ...................................................................... 4–11 

4.9 Power Regulator Circuit Board ........................................................................ 4–12 

4.10 RF Driver/Amplifier (FM30) ............................................................................. 4–12 

4.11 RF Driver (FM100/FM250)............................................................................... 4–13 

4.12 RF Amplifier (FM100/FM250) .......................................................................... 4–13 

4.13 Chassis ........................................................................................................... 4–14 

4.14 RF Output Filter & Reflectometer..................................................................... 4–14 

4.15 Receiver Circuit Board Option ......................................................................... 4–15 

iv

Section 5—Adjustments and Tests ................................. 5–1 

5.1 Audio Processor Adjustments ........................................................................... 5–2 

5.1.1 Pre-Emphasis Selection ................................................................................ 5–2 

5.1.2 Pre-Emphasis Fine Adjustment ..................................................................... 5–2 

5.2 Stereo Generator Adjustments .......................................................................... 5–2 

5.2.1 Separation .................................................................................................... 5–2 

5.2.2 Composite Output ......................................................................................... 5–2 

Using a Modulation Monitor 5–3 

5.2.3 19–kHz Level ................................................................................................ 5–4 

5.2.4 19–kHz Phase ............................................................................................... 5–4 

5.3 Frequency Synthesizer Adjustments .................................................................. 5–4 

5.3.1 Frequency (Channel) Selection ...................................................................... 5–4 

5.3.2 Modulation Compensator .............................................................................. 5–4 

5.3.3 Frequency Measurement and Adjustment ..................................................... 5–4 

5.3.4 FSK Balance Control ..................................................................................... 5–5 

5.4 Metering Board Adjustments ............................................................................. 5–5 

5.4.1 Power Calibrate............................................................................................. 5–5 

5.4.2 Power Set ..................................................................................................... 5–5 

5.4.3 SWR Calibrate............................................................................................... 5–5 

5.4.4 PA Current Limit ........................................................................................... 5–6 

5.5 Motherboard Adjustments ................................................................................. 5–6 

5.6 Display Modulation Calibration .......................................................................... 5–6 

5.7 Voltage Regulator Adjustments ......................................................................... 5–6 

5.8 Bias Set (RF Power Amplifier) ........................................................................... 5–7 

5.9 Performance Verification ................................................................................... 5–7 

5.9.1 Audio Proof-of-Performance Measurements ................................................. 5–7 

5.9.2 De-emphasis Input Network.......................................................................... 5–7 

5.10 Carrier Frequency .............................................................................................. 5–8 

5.11 Output Power .................................................................................................... 5–8 

5.12 RF Bandwidth and RF Harmonics ...................................................................... 5–8 

5.13 Pilot Frequency ................................................................................................. 5–8 

5.14 Audio Frequency Response ............................................................................... 5–9 

5.15 Audio Distortion ................................................................................................ 5–9 

5.16 Modulation Percentage...................................................................................... 5–9 

5.17 FM and AM Noise .............................................................................................. 5–9 

5.18 Stereo Separation .............................................................................................. 5–9 

5.19 Crosstalk ........................................................................................................... 5–9 

5.19.1 Main Channel Into Sub .............................................................................. 5–10 

5.19.2 Sub Channel Into Main .............................................................................. 5–10 

5.20 38–kHz Subcarrier Suppression ...................................................................... 5–10 

5.21 Additional Checks ............................................................................................ 5–10 

v

Section 6—Reference Drawings .................................... 6–1 

6.1 Views ................................................................................................................ 6–2 

6.2 Board Layouts and Schematics ......................................................................... 6–4 

Section 7—Service and Support .................................... 7–1 

7.1 Service .............................................................................................................. 7–2 

7.2 24–Hour Support .............................................................................................. 7–2 

7.3 Spare Parts ....................................................................................................... 7–2 

Transmitter Output Efficiency .............................. Appendix–1 

Glossary ................................................................. G–1 

Index................................................................ Index–1 

vi

I 

INFORMATION 

Section 1—Getting Acquainted 

This section provides a general description of the FM30, FM100, 

and FM250 transmitters and introduces you to safety conventions 

used within this document. Review this material before installing 

or operating the transmitter. 

Getting Acquainted 

1–1

I 

1.1 Your Transmitter 

The FM30, FM100, and FM250 are members of a family of FM stereo broadcast 

transmitters. Crown transmitters are known for their integration, ease-of-use, and 

reliability. 

The integration is most apparent in the standard transmitter configuration which 

incorporates audio processing, stereo generation, and RF amplification without 

compromised signal quality. A single Crown transmitter can replace several pieces 

of equipment in a traditional system. 

Ease-of-use is apparent in the user-friendly front panel interface and in the installation 

procedure. Simply select your operating frequency (using 4 internal 

switches), add an audio source, attach an antenna, and connect AC or DC power 

and you're ready to broadcast. Of course, the FM series of transmitters also feature 

more sophisticated inputs and monitoring connections if needed. 

Reliability is a Crown tradition. The first Crown transmitters were designed for 

rigors of worldwide and potentially portable use. The modular design, quality 

components, engineering approach, and high production standards ensure stable 

performance. 

Remote control and metering of the transmitter is made possible through a builtin 

I/O port. For more direct monitoring, the front panel includes a digital multimeter 

display and status indicators. Automatic control circuitry provides protection 

for high VSWR as well as high current, voltage, and temperature conditions. 

Illustration 1–1 FM250 Stereo Broadcast Transmitter 

This manual describes the FM30, FM100, and FM250 because all three transmitters 

share common design factors. Specific product differences are noted throughout 

the manual. In physical appearance, the FM30 differs from the FM100 and 

FM250 in that it lacks the power amplifier and cooling fan assembly on the back 

panel. 

1–2 FM30/FM100/FM250 User's Manual

1.2 Applications and Options 

Crown transmitters are designed for versatility in applications. They have been used 

as stand-alone and backup transmitters and in booster, translator, satellator, and 

nearcast applications. The following discussion describes these applications further. 

Model numbers describe the configuration of the product (which has to do with its 

intended purpose) and the RF output power which you can expect. 

The number portion of each name represents the maximum RF output power. The 

FM250, for example, can generate up to 250 watts of RF output power. 

Suffix letters describe the configuration. The FM250T, for example, is the standard 

or transmitter configuration. Except where specified, this document describes the 

transmitter configuration. In this configuration, the product includes the following 

components (functions): 

❑ 

❑ 

❑ 

❑ 

❑ 

audio processor 

stereo generator 

RF exciter 

metering 

low-pass filter 

RF Exciter 

Stereo 

Generator 

Low-pass 

Filtering 

Audio 

Processor 

Metering 

® 

FM250 

Illustration 1–2 Standard (Transmitter) Configuration 


1–3

I 

1.2.1 Stand-Alone 

In the standard configuration, the FM30, FM100, and FM250 are ideal stand-alone 

transmitters. When you add an audio source (monaural, L/R stereo, or composite 

signal), an antenna, and AC or DC power, the transmitter becomes a complete FM 

stereo broadcast station, capable of serving a community. 

As stand-alone transmitters, Crown units often replace multiple pieces of equipment 

in a traditional setup (exciter, audio processor, RF amplifier). 

1.2.2 Backup 

In the standard configuration, Crown transmitters are also used in backup applications. 

Should your primary transmitter become disabled, you can continue to 

broadcast while repairs take place. In addition, the FM transmitters can replace 

disabled portions of your existing system including the exciter, audio processor, or 

amplifier. Transfer switches on each side of the existing and backup transmitters 

make the change-over possible with minimal downtime. 

The DC operation option of the FM30, FM100, and FM250 make them attractive 

backup units for those times when AC power is lost. 

1.2.3 Booster 

Also in the standard configuration, Crown transmitters have been used as booster 

transmitters. Booster applications typically involve certain geographic factors 

which prevent your system from broadcasting to the full coverage area allowable. 

For example, a mountain range might block your signal to a portion of your 

coverage area. Careful placement of a Crown transmitter, operating on the same 

frequency as your primary transmitter, can help you reach full coverage. 

1.2.4 Exciter 

In addition to the standard configuration, the FM30, FM100, and FM250 are 

available in optional configurations to meet a variety of needs. 

An "E" suffix, as in the FM30E, for example, represents an exciter-only configuration. 

In this configuration, the audio processor and stereo generator boards are 

replaced with circuitry to bypass their function. The exciter configurations are the 

least expensive way to get Crown-quality components into your transmission 

system. 

You might consider the Crown exciter when other portions of your system are 

performing satisfactorily and you want to maximize your investment in present 

equipment. 


1.2.5 Translator 

A receiver configuration (FM100R, for example) replaces the audio processor and 

stereo generator boards with a receiver module. This added feature makes the 

FM30, FM100, and FM250 ideal for translator service in terrestrial-fed networks. 

These networks represent a popular and effective way to increase your broadcasting 

coverage. Translators, acting as repeater emitters, are necessary links in this chain 

of events. 

Traditionally, network engineers have relied on multiple steps and multiple pieces 

of equipment to accomplish the task. Others have integrated the translator 

function (receiver and exciter) to feed an amplifier. Crown, on the other hand, 

starts with an integrated transmitter and adds a solid-state Receiver Module to 

form the ideal translator. 

Receiver 

Module 

(option) 

Frequency 

Selection 

RF In 


Filter 

RF Out 

RF Exciter 

Metering 

® 

FM250 

Illustration 1–3 Crown's Integrated Translator 

This option enables RF in and RF out on any of Crown’s FM series of transmitters. 

In addition, the module supplies a composite output to the RF exciter portion of 

the transmitter. From here, the signal is brought to full power by the built-in 

power amplifier for retransmission. The Receiver Module has been specifically 

designed to handle SCA channel output up to 100 kHz for audio and high-speed 

data. 

FSK ID programming is built-in to ensure compliance with FCC regulations 

regarding the on-air identification of translators. Simply specify the call sign of 

the repeater station when ordering. Should you need to change the location of the 

translator, replacement FSK chips are available. The Receiver Module option 

should be ordered at the time of initial transmitter purchase. However, an option 

kit is available for field converting existing Crown units. 

In the translator configuration there are differences in the function of the front 

panel, see Section 3 for a description. 


1–5

I 

1.2.6 Satellator 

One additional option is available for all configurations—an FSK Identifier (FSK 

IDer). This added feature enables the FM30, FM100, and FM250 to transmit its 

call sign or operating frequency in a Morse code style. This option is intended for 

use in satellite-fed networks. Transmitters equipped in this fashion are often 

known as "satellators." 

Connect the transmitter to your satellite receiver and the pre-programmed FSK 

IDer does the rest—shifting the frequency to comply with FCC requirements and 

in a manner that is unnoticeable to the listener. The FSK IDer module should be 

ordered at the time you order your transmitter, but is available separately (factory 

programmed for your installation). 


Filter 

RF Out 

Stereo 

Generator 

RF Exciter 

Audio 

Processor 

Metering 

® 

FM250 

Illustration 1–4 Transmitter with FSK IDer Option 

Add the FSK IDer option to the exciter configuration for the most economical 

satellator (a composite input signal is required). 

1.2.7 Nearcasting 

The output power of an FM30 transmitter Can be reduced to a level that could 

Function as a near-cast transmitter. Crown transmitters have been used in this 

way for language translation, for rebroadcasting the audio of sporting events within 

a stadium, and for specialized local radio. The FM30 is the only transmitter that is 

appropriate for this application. 


1.3 Transmitter/Exciter Specifications 

Frequency Range 

RF Power Output 

FM30 

FM100 

FM250 

RF Output Impedance 

Frequency Stability 

Audio Input Impedance 

Audio Input Level 

Pre-emphasis 

Audio Response 

Complete transmitter 

87.9 MHz–108 MHz (76 MHz–90 MHz 

optionally available) 

(VSWR 1.5:1 or better) 

3 - 30 watts, adjustable 



50 Ω 

Meets FCC specifications from 

0-50 degrees C 

50 kΩ bridging, balanced, or 600 Ω 

Selectable for –10 dBm to +10 dBm for 

75 kHz deviation at 400 Hz 

Selectable for 25, 50, or 75 µsec; or 

Flat 

Conforms to 75 µsec pre-emphasis 

curve as follows 

±0.30 dB (50 Hz–10 kHz) 

±1.0 dB (10 kHz–15 kHz) 

Exciter only 

±0.25 dB (50 Hz–15 kHz) 

Distortion (THD + Noise) 


Exciter only 

Less than 0.7% (at 15 kHz) 

Less than 0.3% (50 Hz–15 kHz) 

Stereo Separation 


Exciter only 

Crosstalk 

Better than –40 dB (50 Hz–15 kHz) 

Better than –40 dB (50 Hz–15 kHz) 

Main into sub, better than –40 dB 

Sub into main, better than –40 dB 

Stereo Pilot 

19 kHz ±2 Hz, 9% modulation 


1–7

I 

Subcarrier Suppression 

FM S/N Ratio (FM noise) 


Exciter only 

AM S/N Ratio 

RF Bandwidth 

RF Spurious Products 

50 dB below ±75 kHz deviation 

Better than –60 dB 


Asynchronous and synchronous noise 

better than FCC requirements 

±120 kHz, better than –35 dB 

±240 kHz, better than –45 dB 


Operating Environment Temperature (0 o C –50 o C) 

Humidity (0–80% at 20 o C) 

Maximum Altitude (3,000 meters; 9843 

feet) 

AC Power 100, 120, 220, or 240 volts (+10%/ 

–15%); 50/60 Hz 

FM30 

FM100 

FM250 

115 VA 

297 VA 

550 VA 

DC Power 

FM30 

FM100 and FM250 

24–36 volts (36 volts at 3 amps required for 

full output power) 

36–62 volts [48 volts at 5 amps (FM100) or 

72 volts at 8 amps (FM250) required for 

full output power] 


Note: We set voltage and ampere requirements to assist you in designing your 

system. Depending on your operating frequency, actual requirements for maximum 

voltage and current readings are 10–15% lower than stated. 

Regulatory Type notified for FCC parts 73 and 74 

Meets FCC, DOC, and CCIR requirements 

Dimensions 

Weight 

FM30 

FM100 

FM250 

13.5 x 41.9 x 44.5 cm 

(5.25 x 16.5 x 17.5 inches) 

10.5 kg (23 lbs) 

13.6 kg (30 lbs) shipping weight 

11.4 kg (25 lbs) 


16.8 kg (37 lbs) 



1–9

I 

1.4 Receiver Specifications 

Monaural Sensitivity (demodulated, de-emphasized) 

3.5 µV for signal-to-noise > 50 dB 

Stereo Sensitivity (19–kHz pilot frequency added) 

31 µ V for signal-to-noise > 50 dB 

Connector Standard type N, 50 Ω 

Shipping Weight 1 lb 

1.5 Safety Considerations 

Crown Broadcast assumes the responsibility for providing you a safe product and 

safety guidelines during its use. “Safety” means protection to all individuals who 

install, operate, and service the transmitter as well as protection of the transmitter 

itself. To promote safety, we use standard hazard alert labeling on the product and 

in this manual. Follow the associated guidelines to avoid potential hazard. 

1.5.1 Dangers 

DANGER represents the most severe hazard alert. Extreme bodily harm or death 

will occur if DANGER guidelines are not followed. 

1.5.2 Warnings 

WARNING represents hazards which could result in severe injury or death. 

1.5.3 Cautions 

CAUTION indicates potential personal injury, or equipment or property damage if 

the associated guidelines are not followed. Particular cautions in this text also 

indicate unauthorized radio-frequency operation. 

WARNING 

Severe shock hazard! 

Type of Hazard 

Pictorial Indication 

of Hazard 

Turn power off and 

wait approximately 1 

minute for capacitors 

to discharge before 

handling them. 

Illustration 1–5 Sample Hazard Alert 

Explanation 

of Hazard 


® 

Section 2—Installation 

This section provides important guidelines for installing your transmitter. 

Review this information carefully for proper installation. 

Installation 

2–1

CAUTION 

Possible equipment damage! 

Before operating the transmitter for 

the first time, check for the proper AC 

line voltage setting and frequency 

selection as described in sections 2.2 

and 2.3. 

2.1 Operating Environment 

You can install the FM transmitter in a standard component rack or on a suitable 

surface such as a bench or desk. In any case, the area should be as clean and wellventilated 

as possible. Always allow for at least 2 cm of clearance under the unit for 

ventilation. If you set the transmitter on a flat surface, install spacers on the 

bottom cover plate. If you install the transmitter in a rack, provide adequate 

clearance above and below. Do not locate the transmitter directly above a hot piece 

of equipment. 

2.2 Power Connections 

The FM30, FM100, and FM250 operate on 100, 120, 220, or 240 volts AC (50 or 60 

Hz; single phase). Each transmitter can operate on DC power as well (28 volts for 

the FM30, 36 volts for the FM100, and 62 volts for the FM250). The transmitter 

can operate on fewer volts DC, but with reduced RF output power (see section 1.2). 

In addition, the transmitter isolates the AC and DC sources; both can be connected 

at the same time to provide battery backup in the event of an AC power failure. 

2.2.1 AC Line Voltage Setting 

To change the voltage setting, follow these steps: 

1. Disconnect the power cord if it is attached. 

2. Open the cover of the power connector assembly using a small, flat blade 

screwdriver. See Illustration 2–1. 

3. Insert the screwdriver into the voltage selection slot and remove the drum 

from the assembly. 

4. Rotate the drum to select the desired voltage. See Illustration 2–2. 

5. Replace the drum and cover and check to see that the correct voltage appears 

in the connector window. 

6. Connect the AC power cord. 


120Vac 

Illustration 2–1 Removing the Power Connector Cover 

remove drum 

before turn 

120Vac 

220Vac 

240Vac 

Illustration 2–2 Selecting an AC Line Voltage 

Installation 

2–3

2.2.2 Fuses 

The fuse holders are located in the power connector assembly just below the voltage 

selector. 

120Vac 

220Vac 

240Vac 

remove drum 

before turn 

Illustration 2–3 Fuse Holder 

For 100 to 120 VAC operation, use the fuse installed at the factory. For 220 to 240 

VAC operation, use the slow-blow fuse located in a hardware kit within the 

transmitter packaging. Consult the following table: 

Transmitter Input Power Fuse 

FM30 100–120 V 3 A 

220–240 V 1.5 A 

FM100 100–120 V 6.3 A 

220–240 V 4 A 

FM250 100–120 V 12.5 A 

220–240 V 6.3 A 

Illustration 2–4 Fuse Reference Table 


2.2.3 Battery Power 

Your transmitter can operate on a DC power source (such as 3 or 4, 12–volt automotive 

batteries connected in series). The FM30 requires 28 volts DC for full 

output power, while the FM100 requires 36 volts, and FM250 requires 62 volts for 

full output power. Connect the batteries to the red (+) and black (–) battery input 

binding posts on the rear panel. 

SCA IN COMPOSITE IN MONITOR 

RIGHT 

LEFT/MONO 

R 

L 

REMOTE I/O 

1 

2 3 

DC Input Terminals 

CIRCUIT 

BREAKER 

OFF 

+ 

– 

B 

A 

T 

T 

E 

R 

Y 

36 VDC 

Illustration 2–5 DC Input Terminals 

CAUTION 


Never connect a battery charger to the 

input terminals of the transmitter 

unless a battery is also connected. 

Voltage peaks from a typical charger 

(without the load of a battery) can be 

destructive to the transmitter. 

2.3 Frequency (Channel) Selection 

You may select an operating frequency of 87 to 108 MHz in the FM broadcast band. 

Pins 9 and 10 of HD2 on the RF Exciter board are jumpered for frequencies 

other than these such as the optional Japan frequencies of 76-90 MHz. 

To adjust the operating frequency, follow these steps: 

1. Remove the top cover by removing 18 screws. 

Installation 

2–5

2. Locate the RF Exciter board and identify the frequency selector switches 

which will be used to change the setting. See Illustrations 2–6 and 2–7. 

Modulation 

Trim-pot 

Frequency Selection 

Rotary Switches 

RF Exciter 

® 

FM250 

Illustration 2–6 Top Cover Removed 

OPTIONAL 

MEGAHERTZ .1 .01 

Illustration 2–7 RF Exciter Board (Frequency Selector Switches) 

3. Use small flat blade screwdriver or another suitable device to rotate the 

switches to the desired setting. (The selected number will appear directly 

above the white indicator dot on each switch.) See examples of selected 

frequencies in the illustration below. 

= 88.1 MHz 

= 107.9 MHz 

Illustration 2–8 Two Sample Frequency Selections 


2.3.1 Modulation Compensator 

The Modulation trim-potentiometer (see illustration 2–6) compensates for slight 

variations in deviation sensitivity with frequency. Set the trim-pot dial according to 

the following graph: 

Modulation Compensation Pot Setting 

90 

80 

70 

60 

50 

40 

30 

20 

10 

0 

75 80 85 90 95 100 105 110 

Frequency (MHz) 

Illustration 2–9 Modulation Compensator Settings 

These compensator settings are approximate. Each mark on the potentiometer 

represents about 1.8% modulation compensation. For more exact settings, refer to 

section 5.2.2. 

Installation 

2–7

2.4 Receiver Frequency Selection 

If you have a transmitter equipped with the receiver option, you will need to set the 

receiving or incoming frequency. 

1. With the top cover removed, locate the receiver module and the two switches 

(labeled SW1 and SW2). 

Receiver 

Module 

Frequency Selection Switches 

® 

FM250 

Illustration 2–10 Receiver Module Switches 

2. Use the adjacent chart to set the switches for the desired incoming frequency. 

3. After setting the frequency, replace the top cover and screws. 


Frequency 

SW1 SW2 

87.9 0 0 

88.0 8 0 

88.1 0 1 

88.2 8 1 

88.3 0 2 

88.4 8 2 

88.5 0 3 

88.6 8 3 

88.7 0 4 

88.8 8 4 

88.9 0 5 

89.0 8 5 

89.1 0 6 

89.2 8 6 

89.3 0 7 

89.4 8 7 

89.5 0 8 

89.6 8 8 

89.7 0 9 

89.8 8 9 

89.9 0 A 

90.0 8 A 

90.1 0 B 

90.2 8 B 

90.3 0 C 

90.4 8 C 

90.5 0 D 

90.6 8 D 

90.7 0 E 

90.8 8 E 

90.9 0 F 

91.0 8 F 

91.1 1 0 

91.2 9 0 

91.3 1 1 

91.4 9 1 

91.5 1 2 

91.6 9 2 

91.7 1 3 

91.8 9 3 

91.9 1 4 

92.0 9 4 

92.1 1 5 

92.2 9 5 

92.3 1 6 

92.4 9 6 

92.5 1 7 

92.6 9 7 

92.7 1 8 

92.8 9 8 

92.9 1 9 

Frequency SW1 SW2 

93.0 9 9 

93.1 1 A 

93.2 9 A 

93.3 1 B 

93.4 9 B 

93.5 1 C 

93.6 9 C 

93.7 1 D 

93.8 9 D 

93.9 1 E 

94.0 9 E 

94.1 1 F 

94.2 9 F 

94.3 2 0 

94.4 A 0 

94.5 2 1 

94.6 A 1 

94.7 2 2 

94.8 A 2 

94.9 2 3 

95.0 A 3 

95.1 2 4 

95.2 A 4 

95.3 2 5 

95.4 A 5 

95.5 2 6 

95.6 A 6 

95.7 2 7 

95.8 A 7 

95.9 2 8 

96.0 A 8 

96.1 2 9 

96.2 A 9 

96.3 2 A 

96.4 A A 

96.5 2 B 

96.6 A B 

96.7 2 C 

96.8 A C 

96.9 2 D 

97.0 A D 

97.1 2 E 

97.2 A E 

97.3 2 F 

97.4 A F 

97.5 3 0 

97.6 B 0 

97.7 3 1 

97.8 B 1 

97.9 3 2 

Installation 


98.0 B 2 

98.1 3 3 

98.2 B 3 

98.3 3 4 

98.4 B 4 

98.5 3 5 

98.6 B 5 

98.7 3 6 

98.8 B 6 

98.9 3 7 

99.0 B 7 

99.1 3 8 

99.2 B 8 

99.3 3 9 

99.4 B 9 

99.5 3 A 

99.6 B A 

99.7 3 B 

99.8 B B 

99.9 3 C 

100.0 B C 

100.1 3 D 

100.2 B D 

100.3 3 E 

100.4 B E 

100.5 3 F 

100.6 B F 

100.7 4 0 

100.8 C 0 

100.9 4 1 

101.0 C 1 

101.1 4 2 

101.2 C 2 

101.3 4 3 

101.4 C 3 

101.5 4 4 

101.6 C 4 

101.7 4 5 

101.8 C 5 

101.9 4 6 

102.0 C 6 

102.1 4 7 

102.2 C 7 

102.3 4 8 

102.4 C 8 

102.5 4 9 

102.6 C 9 

102.7 4 A 

102.8 C A 

102.9 4 B 

Illustration 2–11 Receiver Frequency Selection 


103.0 C B 

103.1 4 C 

103.2 C C 

103.3 4 D 

103.4 C D 

103.5 4 E 

103.6 C E 

103.7 4 F 

103.8 C F 

103.9 5 0 

104.0 D 0 

104.1 5 1 

104.2 D 1 

104.3 5 2 

104.4 D 2 

104.5 5 3 

104.6 D 3 

104.7 5 4 

104.8 D 4 

104.9 5 5 

105.0 D 5 

105.1 5 6 

105.2 D 6 

105.3 5 7 

105.4 D 7 

105.5 5 8 

105.6 D 8 

105.7 5 9 

105.8 D 9 

105.9 5 A 

106.0 D A 

106.1 5 B 

106.2 D B 

106.3 5 C 

106.4 D C 

106.5 5 D 

106.6 D D 

106.7 5 E 

106.8 D E 

106.9 5 F 

107.0 D F 

107.1 6 0 

107.2 E 0 

107.3 6 1 

107.4 E 1 

107.5 6 2 

107.6 E 2 

107.7 6 3 

107.8 E 3 

107.9 6 4 

108.0 E 4 

2–9

2.5 RF Connections 

Connect the RF load, an antenna or the input of an external power amplifier, to the 

type-N, RF output connector on the rear panel. VSWR should be 1.5:1 or better. 

WARNING 

Severe shock hazard! 

Do not touch the inner 

portion of the RF 

output connector 

when transmitter 

power is on. 

The RF monitor is intended primarily for a modulation monitor connection. 

Information gained through this connection can supplement that which is available 

on the transmitter front panel displays. 

If your transmitter is equipped with the receiver option, connect the incoming RF 

to the RF IN connector. 

RF Output 

Connector 

RF Input Connector 

(receiver option only) 

RF Output 

Monitor 

120Vac 

Illustration 2–12 RF Connections 


2.6 Audio Input Connections 

Attach audio inputs to the Left and Right XLR connectors on the rear panel. (The 

Left channel audio is used on Mono.) Pin 1 of the XLR connector goes to chassis 

ground. Pins 2 and 3 represent a balanced differential input with an impedance of 

about 50 kΩ. They may be connected to balanced or unbalanced left and right 

program sources. 

The audio input cables should be shielded pairs, whether the source is balanced or 

unbalanced. For an unbalanced program source, one line (preferably the one 

connecting to pin 3) should be grounded to the shield at the source. Audio will 

then connect to the line going to pin 2. 


RIGHT 

LEFT/MONO 

R 

L 

REMOTE I/O 

1 

2 3 

Audio Inputs 

CIRCUIT 

BREAKER 

OFF 

+ 

– 

B 

A 

T 

T 

E 

R 

Y 

36 VDC 

Illustration 2–13 XLR Audio Input Connectors 

By bringing the audio return line back to the program source, the balanced 

differential input of the transmitter is used to best advantage to minimize noise. 

This practice is especially helpful if the program lines are fairly long, but is a good 

practice for any distance. 

If the program source requires a 600 Ω termination, see the motherboard 

configuration chart on page 6-14 for the proper configuration of the jumpers. 

Installation 

2–11

2.7 SCA Input Connections 

You can connect external SCA generators to the SCA In connectors (BNC-type) on 

the rear panel. The inputs are intended for the 60 kHz to 99 kHz range, but a lower 

frequency may be used if the transmitter is operated in Mono mode. (The 23 to 53 

kHz band is used for stereo transmission.) For 7.5 kHz deviation (10% 

modulation), input of approximately 3.5–volts (peak-to-peak) is required. 


RIGHT 

LEFT/MONO 

R 

L 

REMOTE I/O 

1 

2 3 

SCA Inputs 

CIRCUIT 

BREAKER 

OFF 

+ 

– 

B 

A 

T 

T 

E 

R 

Y 

36 VDC 

Illustration 2–14 SCA Input Connectors 

2.8 Composite Input Connection 

You may feed composite stereo (or mono audio) directly to the RF exciter, bypassing 

the internal audio processor and stereo generator. To use the Crown transmitter as 

an RF Exciter only ("E" version or when using the "T" version with composite 

input), it is necessary to use the Composite Input section of the transmitter. This 

will feed composite stereo (or mono audio) directly to the RF exciter. In the "T" 

version, this will bypass the internal audio processor and stereo generator. 

Input sensitivity is approximately 3.5–volt P-P for 75 kHz deviation. 

1. Enable the Composite Input by grounding pin 9 of the Remote I/O 

connector (see Illustration 2–17). 

2. Connect the composite signal using the Composite In BNC connector. 



RIGHT 

LEFT/MONO 

R 

L 

REMOTE I/O 

1 

2 3 

Composite In 

BNC Connector 

CIRCUIT 

BREAKER 

OFF 

+ 

– 

36 VDC 

B 

A 

T 

T 

E 

R 

Y 

Audio Monitor Jacks 

Illustration 2–15 Composite In and Audio Monitor Connections 

2.9 Audio Monitor Connections 

Processed, de-emphasized samples of the left and right audio inputs to the stereo 

generator are available at the Monitor jacks on the rear panel. The signals are 

suitable for feeding a studio monitor and for doing audio testing. De-emphasis is 

normally set for 75 µsec; set to 50 µsec by moving jumpers, JP203 and JP204, on 

the Stereo Generator board. 

2.10 Pre-emphasis Selection 

Select the pre-emphasis curve (75 µsec, 50 µsec, 25 µsec, or Flat) by jumpering the 

appropriate pins of header JP1 on the audio processor board. If you change the preemphasis, 

change the de-emphasis jumpers JP203 and JP204 on the Stereo 

Generator board to match. 

Installation 

2–13

2.11 Program Input Fault Time-out 

You can enable an automatic turn-off of the carrier in the event of program failure. 

To enable this option, see illustration 2-17 on page 2-15. The time between program 

failure and carrier turn-off is set by a jumper (JP1) on the voltage regulator board 

(see page 6–17 for board location). Jumper pins 1 and 2 (the two pins closest 

to the edge of the board) for a delay of approximately 30 seconds; pins 3 and 4 for a 

2–minute delay; pins 5 and 6 for a 4–minute delay, and pins 7 and 8 for an 8– 

minute delay. 

2.12 Remote I/O Connector 

Remote control and remote metering of the transmitter is made possible through a 

15–pin, D-sub connector on the rear panel. (No connections are required for 

normal operation.) 

Remote I/O 


RIGHT 

LEFT/MONO 

R 

L 

REMOTE I/O 

1 

2 3 

CIRCUIT 

BREAKER 

OFF 

+ 

– 

B 

A 

T 

T 

E 

R 

Y 

36 VDC 

Illustration 2–16 Remote I/O Connector 

Illustration 2-17 on page 2-15 summarizes the Remote I/O pin connections. 


Pin Number 

Function 

1 Ground 

2 (no connection) 

3 Composite Out (sample of stereo generator output) 

4 FSK In (Normally high; pull low to shift carrier frequency 

approximately 7.5 kHz. Connect to open collector or relay 

contacts of user-supplied FSK keyer.) 

5 /Auto Carrier Off (Pull low to enable automatic turnoff of 

carrier with program failure.) 

6 Meter Battery (unregulated DC voltage; 5 volts = 50 VDC) 

7 Meter RF Watts (1 volt = 100 watts) 

8 Meter PA Volts (5 volts = 50 VDC) 

9 /Ext. Enable (Pull low to disable internal stereo generator 

and enable External Composite Input.) 

10 a) 38 kHz Out (From stereo generator for power supply 

synchronization.) 

11 ALC 

b) For transmitters equipped with tuner option, this pin 

becomes the right audio output for an 8–ohm monitor 

speaker. 38kHZ Out is disabled. 

12 /Carrier Off (pull low to turn carrier off.) 

13 Fault Summary (line goes high if any fault light is 

activated.) 

14 Meter PA Temperature (5 volts = 100 degrees C.) 

15 Meter PA Current (1 volt = 10 amperes DC.) 

8 

1 

15 

9 

Illustration 2–17 Remote I/O Connector (DB-15 Female) 

Installation 

2–15

Notes: 


Section 3—Operation 

This section provides general operating parameters of your 

transmitter and a detailed description of its front panel display. 

Operation 

3–1

3.1 Initial Power-up Procedures 

These steps summarize the operating procedures you should use for the initial 

operation of the transmitter. More detailed information follows. 

CAUTION 


Before operating the transmitter for 

the first time, check for the proper AC 

line voltage setting and frequency 

selection as described in sections 2.2 

and 2.3. 

1. Turn on the DC breaker. 


RIGHT 

LEFT/MONO 

R 

REMOTE I/O 

L 

DC Breaker 

1 

2 3 

CIRCUIT 

BREAKER 

OFF 

+ 

– 

B 

A 

T 

T 

E 

R 

Y 

36 VDC 

Illustration 3–1 DC Breaker 

2. Turn on the main power switch. 

Carrier 

Switch 

Main Power 

Switch 

Illustration 3–2 Front Panel Power Switches 

3–2 FM30/100/250 User's Manual

3. Verify the following: 

a. The bottom cooling fan runs continuously. 

b. The Lock Fault indicator flashes for approximately 5 seconds, then 

goes off. 

4. Set the Input Gain switches for mid-scale wideband gain reduction on an 

average program level (see section 3.4). 

5. Set the Processing control (see section 3.5; normal setting is “50”). 

6. Set the Stereo-Mono switch to Stereo (see section 3.6). 

7. Turn on the Carrier switch. 

8. Check the following parameters on the front panel multimeter: 

a. RF Power should be 29–33 watts for the FM30, 95–110 watts for the 

FM100, and 250–275 watts for the FM250. 

b. SWR should be less than 1.1. (A reading greater than 1.25 indicates an 

antenna mismatch. 

c. ALC should be between 4.00 and 6.00 volts. 

d. PA DC Volts should be 26–30 volts for the FM30, 25–35 volts for the 

FM100, and 37–52 volts for the FM250. (Varies with antenna match, 

power, and frequency.) 

e. PA DC Amperes should be 1.5–2.5 amps for the FM30, 4.5–6.5 amps 

for the FM100, and 6.0–8.0 amps for the FM250. (Varies with antenna 

match, power, and frequency.) 

f. PA Temperature should initially read 20–35 degrees C (room temperature). 

After one hour the reading should be 35–50 degrees C. 

g. Supply DC Volts should display a typical reading of 45 V with the 

carrier on and 50 V with the carrier off for both the FM30 and FM100 

products. For the FM250, the readings should be 65 V with the carrier 

on and 75 V with carrier off. 

h. Voltmeter should be reading 0.0. 

The remainder of this section describes the functions of the front panel indicators 

and switches. 

Operation 

3–3

3.2 Power Switches 

3.2.1 DC Breaker 

The DC breaker, on the rear panel, must be on (up) for transmitter operation, even 

when using AC power. Electrically, the DC breaker is located immediately after 

diodes which isolate the DC and AC power supplies. 

3.2.2 Power Switch 

The main on/off power switch controls both the 120/240 VAC and the DC battery 

power input. 

3.2.3 Carrier Switch 

This switch controls power to the RF amplifiers and supplies a logic high to the 

voltage regulator board, which enables the supply for the RF driver. In addition, 

the Carrier Switch controls the operating voltage needed by the switching power 

regulator. 

A "Lock Fault" or a low pin 12 (/Carrier Off) on the Remote I/O connector will hold 

the carrier off. (See section 2.12.) 

Carrier 

Switch 

Main Power 

Switch 

Illustration 3–3 Front Panel Power Switches 


3.3 Front Panel Bar-Dot Displays 

Bar-dot LEDs show audio input levels, wideband and highband audio gain control, 

and modulation percentage. Resolution for the gain control and modulation displays 

is increased over a conventional bar-graph display using dither enhancement which 

modulates the brightness of the LED to give the effect of a fade from dot to dot. (See 

section 4.7.) 

3.3.1 Audio Processor Input 

Two vertical, moving-dot displays for the left and right channels indicate the relative 

audio levels, in 3 dB steps, at the input of the audio processor. Under normal operating 

conditions, the left and right Audio Processor indicators will be active, indicating 

the relative audio input level after the Input Gain switches. During program pauses, 

the red Low LED will light. 

The translator configuration shows relative audio levels from the included receiver. 

3.3.2 Highband and Wideband Display 

During audio processing, the moving-dot displays indicate the amount of gain control 

for broadband (Wide) and pre-emphasized (High) audio. 

As long as program material causes activity of the Wideband green indicators, determined 

by the program source level and Input Gain switches, the transmitter will be 

fully modulated. (See section 3.4.) 

The Wideband indicator shows short-term “syllabic-rate” expansion and gain reduction 

around a long-term (several seconds) average gain set. In the translator configuration, 

the Wideband indicator also shows relative RF signal strength. 

Program material and the setting of the Processing control determine the magnitude 

of the short-term expansion and compression (the rapid left and right movement of 

the green light). 

High-frequency program content affects the activity of the Highband indicator. With 

75–µsec pre-emphasis, Highband processing begins at about 2 kHz and increases as 

the audio frequency increases. Some programs, especially speech, may show no 

activity while some music programs may show a great deal of activity. 

3.3.3 Modulation Display 

A 10–segment, vertical peak-and-hold, bar graph displays the peak modulation percentage. 

A reading of “100” coincides with 75 kHz deviation. The display holds 

briefly (about 0.1 seconds) after the peak. The “Pilot” indicator illuminates when the 

transmitter is in the stereo mode. 

To verify the actual (or more precise) modulation percentage, connect a certified 

modulation monitor to the RF monitor jack on the rear panel. 

Operation 

3–5

3.4 Input Gain Switches 

The “+6 dB” and “+12 dB” slide switches set audio input sensitivity according to 

the following table. 

Nominal Input Switches 

Sensitivity +6 dB +12 dB 

+10 dBm Down Down 

+4 dBm Up Down 

-2 dBm Down Up 

-8 dBm Up Up 

Illustration 3–4 Input Gain Switches 

Find, experimentally, the combination of Input Gain switch settings that will bring 

the Wideband gain-reduction indicator to mid scale for “normal” level program 

material. The audio processor will accommodate a fairly wide range of input levels 

with no degradation of audio quality. 

3.5 Processing Control 

Two factors contribute to the setting of the Processing control: program material 

and personal taste. For most program material, a setting in the range of 40 to 70 

provides good program density. For the classical music purist, who might prefer 

preservation of music dynamics over density, 10 to 40 is a good range. The audio 

will be heavily processed in the 70 to 100 range. 

If the program source is already well processed, as might be the case with a satellite 

feed, set the Processing to “0” or “10”. 

3.6 Stereo-Mono Switch 

The Stereo-Mono slide switch selects the transmission mode. In Mono, feed audio 

only to the left channel. Although right-channel audio will not be heard as audio 

modulation, it will affect the audio processing. 


3.7 RF Output Control 

Set this control for the desired output power level. Preferably, set the power with 

an external RF wattmeter connected in the coaxial line to the antenna. You may 

also use the RF power reading on the digital multimeter. 

The control sets the RF output voltage. Actual RF output power varies as the 

approximate square of the relative setting of the control. For example, a setting of 

“50” is approximately 1/4 full power. 

3.8 Digital Multimeter 

The four-digit numeric display in the center of the front panel provides information 

on transmitter operation. Use the “Up” and “down” push-buttons to select 

one of the following parameters. A green LED indicates the one selected. 

Multimeter Multimeter Functions Multimeter Push-buttons 

Illustration 3–5 Digital Multimeter 

RF Power—Actually reads RF voltage squared, so the accuracy can be affected by 

VSWR (RF voltage-to-current ratio). See section 5.4 for calibration. Requires 

calibration with the RF reflectometer being used. 

SWR—Direct reading of the antenna standing-wave ratio (the ratio of the desired 

load impedance, 50 ohms, to actual load). 

ALC—DC gain control bias used to regulate PA supply voltage. With the PA power 

supply at full output voltage, ALC will read about 6.0 volts. When the RF output is 

being regulated by the RF power control circuit, this voltage will be reduced, 

typically reading 4 to 5.5 volts. The ALC voltage will be reduced during PA DC 

overcurrent, SWR, or LOCK fault conditions. 

Operation 

3–7

PA DC Volts—Supply voltage of the RF power amplifier. 

PA DC Amps—Transistor drain current for the RF power amplifier. 

PA DC Temperature—Temperature of the RF power amplifier heatsink in degrees C. 

Supply DC Volts—Unregulated DC voltage at the input of the voltage regulators. 

For battery operation, this reading is the battery voltage minus a diode drop. 

Voltmeter—Reads the voltage at a test point located on the front edge of the motherboard. 

A test lead connected to this point can be used for making voltage measurements 

in the transmitter. The test point is intended as a servicing aid; an alternative 

to an external test meter. Remember that the accuracy is only as good as the reference 

voltage used by the metering circuit. Servicing a fault affected by the reference 

affects the Voltmeter reading. The metering scale is 0 to 199.9 volts. 

In the translator configuration, you can read a relative indication of RF signal 

strength numerically in the Voltmeter setting. 

3.9 Fault Indicators 

Faults are indicated by a blinking red light as follows: 

SWR—Load VSWR exceeds 1.5:1. ALC voltage is reduced to limit the reflected RF 

power. 

Lock—Frequency synthesizer phase-lock loop is unlocked. This indicator normally 

blinks for about five seconds at power turn-on. Whenever this light is blinking, 

supply voltages will be inhibited for the RF driver stage as well as for the RF power 

amplifier. 

Input—The automatic carrier-off circuit is enabled (see sections 2.11 and 2.12) and 

the absence of a program input signal has exceeded the preset time. (The circuit 

treats white or pink noise as an absence of a program.) 

PA DC—Power supply current for the RF power output amplifier is at the preset 

limit. ALC voltage has been reduced, reducing the PA supply voltage to hold supply 

current to the preset limit. 

PA Temp—PA heatsink temperature has reached 50° C (122° F) for the FM30 and 

70° C (158° F)for the FM100 and FM250. 

At about 55° C (131°F) for the FM30 or 72°C (162° F) for the FM100 and FM250, 

ALC voltage begins to decrease, reducing the PA supply voltage to prevent a further 

increase in temperature. By 60° C (140° F) for the FM30 and 75° C (167° F) for the 

FM100 and FM250, the PA will be fully cut off. The heatsink fan (models FM100 

and FM250 only) is proportionally controlled to hold the heatsink at 35 ° C (95° F). 

Above this temperature, the fan runs at full speed. 


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Section 4—Principles of Operation 

This section discusses the circuit principles upon which the 

transmitter functions. This information is not needed for day-today 

operation of the transmitter but may be useful for advanced 

users and service personnel. 

Principles of Operation 

4–1

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4.1 Part Numbering 

As this section refers to individual components, you should be familiar with the 

part numbering scheme used. Although parts on the various circuit boards and 

circuit board drawings may be marked with identical reference numbers, each 

component in the transmitter has a unique part reference number. 

The circuit boards and component placement drawings use designators such as 

“R1”, “R2”, and “C1.” These numbers represent only a portion of the full part 

numbers (as shown on the schematic). To find the full number, refer to the chart 

below. R401, for instance, is marked “R1” on the Metering board and on its 

component placement drawing. 

Circuit Name 

Part numbers 

Audio Processor 0-199 

Stereo Generator 200’s 

RF Exciter/Synthesizer 300’s 

Metering/Protection 400’s 

Motherboard 500’s 

Display 600’s 

Voltage Regulator 700’s 

Power Regulator 800’s 

RF Predriver 900’s 

Chassis Wiring 

RF Power Amplifier 

RF Low-Pass Filter 

1000's 

1100's 

1200's 

Illustration 4–1 Component Part Numbering 


4.2 Audio Processor Circuit Board 

The audio processor board provides the audio control functions of a compressor, 

limiter, and expander. Illustration 6–5 and accompanying schematic may be useful 

to you during this discussion. 

Audio 

Processor 

Board 

FM250 

Illustration 4–2 Audio Processor Board 

This board also contains the pre-emphasis networks. Reference numbers are for the 

left channel. Where there is a right-channel counterpart, references are in 

parenthesis. One processor circuit, the eighth-order elliptical filter, is located on 

the stereo generator board. 

Audio input from the XLR connector on the rear panel of the transmitter goes to 

differential-input amplifier, U1A (U2A). 

Binary data on the +6 dB and +12 dB control lines sets the gain of inverting 

amplifier U1B (U2B). Analog switch, U3, selects one of four feedback points in 6–dB 

steps. 

The output of U1B (U2B) goes to an eighth-order, elliptical, switched-capacitor, 

low-pass, 15.2–kHz filter. The filter finds its home on the stereo generator board to 

take advantage of the ground plane and proximity to the 1.52 MHz clock. 

The circuit associated with U4B (U4A), along with R22/C8 (R58/C20), form 

third-order, low-pass filtering, attenuating audio products below 30 Hz. 

The output level of analog multiplier U5 (U6) is the product of the audio signal at 

pin 13 and the DC voltage difference between pins 7 and 9. At full gain (no gain 

reduction) this difference will be 10 volts DC. 


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When either the positive or negative peaks of the output of U5 (U6) exceeds the 

gain-reduction threshold, U13A generates DC bias, producing broadband gain 

reduction. Q5 is a precision-matched transistor pair. Q5 and U13B form a log 

converter, so that a given voltage change produces a given change in gain control 

dB of U5 (U6). The log conversion ensures uniform level-processing characteristics 

well beyond the 20–dB control range. The log conversion has an additional benefit; 

it allows a display of gain control on a linear scale with even distribution of dB. 

Q1 (Q2) is a recover/expansion gate with a threshold about 18 dB below the normal 

program level. The amount of short-term expansion and gain reduction is 

controlled by R650, located on the front panel display board. (See section 3.5.) 

Pre-emphasis, in microseconds, is the product of the capacitance of C10 (C22), 

multiplied by the gain of U8 (U9), times the value of R31 (R67). For a 75–µsecond 

pre-emphasis, the gain of U8 (U9) will be about 1.11. Select the pre-emphasis curve 

(75 µsec, 50 µsec, 25 µsec, or Flat) by jumpering the appropriate pins on header 

JP1. Use trim pot R29 (R65) to make fine adjustments to the pre-emphasis. (See 

section 5.1.) 

For highband processing, the peak output of U10B is detected and gain-reduction 

bias is generated, as with the broadband processor. The highband processing, 

however, shifts the pre-emphasis curve rather than affecting overall gain. 

Peak audio voltages are compared to a plus and minus 5–volt reference, U17 and 

U18. This same reference voltage is used by the stereo generator, metering, and 

display boards. 

For an explanation of on-board adjustments see section 5.1. 

4.3 Stereo Generator Circuit Board 

The stereo generator board (see Illustration 4–3) generates a composite stereo signal 

from left and right-channel audio inputs. The component side of the board is 

mostly a ground plane. Once again, the eighth-order, 15.2–kHz, elliptical, low-pass 

filters (U201 and U202) are on this board, but belong to the audio processor. 

Illustration 6–6 and accompanying schematic complement this discussion. 

U207A and Y201 comprise a 7.6–MHz crystal oscillator from which the 19 and 38– 

kHz subcarriers are digitally synthesized. U207F is a buffer. The 7.6 MHz is divided 

by 5 in U208A to provide 1.52 MHz at pin 6, used by filters U201 and U202. 3.8 

MHz, 1.9 MHz, and 304 kHz are also derived from dividers in U208. 

Exclusive-OR gates, U210A and U210B, provide a stepped approximation of a 38–kHz 

sine wave—a scheme described in the CMOS Cookbook by Don Lancaster (Howard 

W. Sams &. Co., Inc., Indianapolis, IN, 1978). 

With the resistor ratios used, the synthesized sine wave has very little harmonic 

energy below the 7th harmonic. U210C and D generate the 19–kHz pilot subcarrier. 

U211 is a dual, switched-capacitor filter, configured as second-order, low-pass filters, 


Stereo 

Generator 

Board 

® 

FM250 

Illustration 4–3 Stereo Generator Board 

each with a Q of 5. The 38 and 19–kHz outputs of pins 1 and 20, respectively, are 

fairly pure sine waves. Harmonic distortion products are better than 66 dB 

down—THD of less than 0.05%. 

U212 is a precision, four-quadrant, analog multiplier. The output of U212 is the 

product of 38 kHz applied to the “X” input and the difference of left and right 

audio (L-R signal) applied to the “Y” input. The resulting output is a double 

sideband, suppressed carrier—the L-R subcarrier. 

The SCA subcarrier, the left, right, and left-minus-right subcarriers, and the 19– 

kHz pilot subcarrier are combined into the composite stereo signal by summing 

amplifier U206B. 

Analog switch U205, at the input of U206B, provides switching of left and right 

audio for stereo and mono modes. In the mono mode, right channel audio is 

disabled, and the left channel audio is increased from 45% modulation to 100%. 

MON L and MON R outputs go to the AF Monitor jacks on the rear panel. 

R208+R210 (R220+R222) and C207 (C211) comprise a 75–µsec de-emphasis 

network. Processed, de-emphasized (75–µsec) samples of the stereo generator 

input signals are used for a studio monitor and for audio testing. Option jumpers 

JP203 (JP204) allow you to select 50 µsec. 

VR201 and VR202 supply +6 volts and –6 volts, respectively. A 5–volt reference 

from the audio processor board supplies the subcarrier generators. 

For an explanation of on-board adjustments see section 5.2. 


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4.4 RF Exciter Circuit Board 

This board is also known as the Frequency Synthesizer board. The entire 

component side of the board is a ground plane. Frequency selector switches along 

the front edge of the board establish the operating frequency. The VCO 

(voltage-controlled oscillator) circuitry is inside an aluminum case. 

Illustration 6–7 and accompanying schematic can be used as reference in this 

discussion. 

VCO61 operates at the synthesizer output frequency of 87 MHz to 108 MHz. 

The frequency is controlled by a voltage applied to pin 8 of the VCO. 

A sample of the RF comes from A2 and is fed to the PLL chip U6. 

U304 is a phase-locked-loop frequency synthesizer IC. The 10.24 MHz from the 

crystal oscillator is divided to 10 kHz. Internal programmable dividers divide the 

87 - 108 MHz RF to 10 kHz. Differences between the two signals produce error 

RF 

Exciter 

Board 

® 

FM250 



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4.5 Metering Circuit Board 

The ALC and metering circuitry is on the metering board (see Illustration 4–5). 

This board processes information for the RF and DC metering, and produces ALC 

(RF level-control) bias. It also provides reference and input voltages for the digital 

panel meter, voltages for remote metering, fan control, and drive for the 

front-panel fault indicators. 


PA voltage and current come from a metering shunt on the power regulator board. 

The PAI input is a current proportional to PA current; R405 converts the current 

to voltage used for metering and control. A voltage divider from the PAV line is 

used for DC voltage metering. 

Metering 

Board 

® 

FM250 

Illustration 4–5 Metering Board 

U406A, U406B, and U407A, with their respective diodes, are diode linearity 

correction circuits. Their DC inputs come from diode detectors in the RF 

reflectometer in the RF low-pass filter compartment. 

U407B, U407C, Q405, and Q406 are components of a DC squaring circuit. Since 

the DC output voltage of U407C is proportional to RF voltage squared, it is also 

proportional to RF power. 

U404C, U404A, U403A, and U404D are level sensors for RF power, reflected RF 

power, PA temperature, and external PA current, respectively. When either of 

these parameters exceeds the limits, the output of U404B will be forced low, 

reducing the ALC (RF level control) voltage, which, in turn, reduces the PA supply 

voltage. 

The DC voltage setpoint for U404A (reflected RF voltage) is one-fifth that of U404C 

(forward RF voltage). This ratio corresponds to an SWR of 1.5:1 [(1+.2)/(1– 

.2)=1.5]. The U405 inverters drive the front panel fault indicators. 


To get a direct reading of SWR, the reference input of the digital panel meter is fed 

from a voltage proportional to the forward-minus-reflected RF voltage, while 

forward-plus-reflected is fed to the digital panel meter input. The panel meter 

provides the divide function. 

U408 and U409 function as data selectors for the digital panel meter input and 

reference voltages. Binary select data for U408 and U409 comes from the display 

board. 

The output voltage of U403D goes positive when the temperature exceeds about 35 

degrees C (set by R426) providing proportional fan control (FM100 and FM250). 

When the Carrier switch is off or the RF power is less than about 5 watts, the SWR 

automatically switches to a calibrate-check mode. U406C provides a voltage that 

simulates forward power, while Q403 shunts any residual DC from the reflectedpower 

source. The result is a simulation of a 1.0 to 1 SWR. (See section 5.4.) 

4.6 Motherboard 

The motherboard is the large board in the upper chassis interconnecting the audio 

processor, stereo generator, RF exciter, and metering boards. The motherboard 

provides the interconnections for these boards, eliminating the need for a wiring 

harness, and provides input/output filtering. 

It also contains the +5.00 volt reference and the composite drive Op amp and its 

associated circuitry. 

This board has configuration jumpers associated with diffeent options that can be 

added at the time of order or at a later time as an upgrade. Options include 

FMX-DMS, FMX-RMS, Crown/Omnia DP3, and other standard options. 


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4.7 Display Circuit Board 

The front-panel LEDs, the numeric display, the slide switches, and the processing 

and RF level controls are mounted on the display circuit board. To access the 

component side of the board, remove the front panel by removing 12 screws. The 

board contains circuits for the digital panel meter, modulation peak detector, and 

LED display drivers, as well as indicators and switches mentioned above. 


Left and right audio from input stages of the audio processor board (just after the 

Input Gain attenuator) go to the L VU and R VU input on the display board. Peak 

rectifiers U601A and U601B drive the left and right Audio Input displays. The LED 

driver gives a 3–dB per step display. The lowest step of the display driver is not 

used; rather a red LOW indicator lights when audio is below the level of the second 

step. Transistors Q601 and Q602 divert current from the LOW LEDs when any 

other LED of the display is lit. 

Resolution of the linear displays, High Band, Wide Band, and Modulation, has been 

improved using dither enhancement. With dither, the brightness of the LED is 

controlled by proximity of the input voltage relative to its voltage threshold. The 

effect is a smooth transition from step to step as input voltage is changed. U606A, 

U606B, and associated components comprise the dither generator. Dither output 

is a triangular wave. 

Composite stereo (or mono) is full-wave detected by diodes D605 and D606. U607, 

U613, Q603, and Q604 are components of a peak sample-and-hold circuit. 

Oscillator, U609F, supplies a low-frequency square wave to the Fault indicators, 

causing them to flash on and off. 

Digital multimeter inputs are selected with push buttons located to the right of 

the multimeter menu. Signals from the push buttons are conditioned by U609A 

and U609B. U610 is an up/down counter. Binary input to U611 from U610 selects 

a green menu indicator light, and lights the appropriate decimal point on the 

numeric readout. The binary lines also go to analog data selectors on the ALC/ 

metering board. 

Processing control, R650, is part of the audio processor. (See section 4.2.) 

The DPM IN and DPM REF lines are analog and reference voltage inputs to digital 

multimeter IC U612. They originate from analog data selectors on the ALC/ 

metering board. 


4.8 Voltage Regulator Circuit Board 

The voltage regulator board is the longer of two boards mounted under the chassis 

toward the front of the unit. It has switch-mode voltage regulators to provide +12, 

–12, and 20 volts. It also contains the program detection and automatic carrier 

control circuits. 


U703E and U703F convert a 38–kHz sine wave from the stereo generator into a 

synchronization pulse. In the transmitter, synchronization is not used, thus D709 

is omitted. 

U704 and U705 form a 20–volt switching regulator running at about 35 kHz. U704 

is used as a pulse-width modulator; U705 is a high-side driver for MOSFET switch 

Q701. Supply voltage for the two IC’s (approximately 15.5 volts) comes from linear 

regulator DZ702/Q705. Bootstrap voltage, provided by D710 and C714, allows the 

gate voltage of Q701 to swing about 15 volts above the source when Q701 is turned 

on. Current through the FET is sensed by R738 and R738A. If the voltage 

between pin 5 and 6 of U705 exceeds 0.23 volts on a current fault, drive to Q701 is 

turned off. Turn-off happens cycle by cycle. The speed of the turn-off is set by 

C713. 

U706 is a switching regulator for both +12 volts and –12 volts. It runs at about 52 

kHz. Energy for –12 volts is taken from inductor L702 during the off portion of 

the switching cycle. The –12 volts tracks the +12 volts within a few tenths of a 

volt. There will be no –12 volts until current is drawn from the +12 volts. 

Q702, Q703, and Q704 form an active filter and switch, supplying DC voltage to 

the RF driver, when the Carrier switch is on. 

The program detection circuit is made up of U701 and U702. U701A and U701D 

and associated circuitry discriminate between normal program material and white 

noise (such as might be present from a studio-transmitter link during program 

failure) or silence. U701A and surrounding components form a band-pass filter 

with a Q of 3 tuned to about 5 kHz. U701D is a first-order low-pass filter. Red and 

green LEDs on the board indicate the presence or absence of program determined 

by the balance of the detected signals from the two filters. U702 and U701C form a 

count-down timer. The time between a program fault and shutdown is selected by 

jumpering pins on header JP701. For times, see section 5.7. The times are 

proportional to the value of R721 (that is, times can be doubled by doubling the 

value of R721) and are listed in minutes. 


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4.9 Power Regulator Circuit Board 

The power regulator board is the shorter of two boards mounted under the chassis 

toward the front of the unit. The board has the isolating diode for the battery 

input, the switch-mode voltage regulator for the RF power amplifier, and circuitry 

for PA supply current metering. 


Diode D804, in series with the battery input, together with the AC-supply diode 

bridge, provides diode OR-ing of the AC and DC supplies. 

U801 and U802 form a switching regulator running at about 35 kHz. U801 is used 

as a pulse-width modulator; U802 is a high-side driver for MOSFET switch Q801. 

Power for the two IC’s comes from the 20–volt supply voltage for the RF driver 

(available when the Carrier switch is on). The voltage is controlled at 16 volts by 

zener diode DZ801. Bootstrap voltage provided by D802 and C809 allows the gate 

voltage of Q801 to swing about 16 volts above the source when Q801 is turned on. 

Current through the FET is sensed by R812A and R812B. If the voltage from pin 5 

to 6 of U802 exceeds 0.23 volts on a current fault, drive to Q801 is turned off. This 

happens on a cycle-by-cycle basis. The speed of the turnoff is set by C805. 

U803 and Q802 are used in a circuit to convert the current that flows through 

metering shunt, R819, into a current source at the collector of Q803. Forty 

millivolts is developed across R819 for each amp of supply current (.04 ohms x 1 

amp). Q803 is biased by U803 to produce the same voltage across R816. The 

collector current of Q803 is the same (minus base current) as that flowing through 

R822 resulting in 40 microamperes per amp of shunt current. R405 on the 

metering board converts Q803 collector current to 0.1 volt per amp of shunt 

current (.04 ma X 2.49 k). (See section 5.4.) 

4.10 RF Driver/Amplifier (FM30) 

The RF Driver/Amplifier assembly is mounted on a 100 mm x 100 mm plate in the 

under side of the chassis. The driver amplifies the approximate 20 milliwatts from 

the frequency synthesizer to 30 watts. An MHW6342T hybrid, high-gain, wideband 

amplifier, operating at about 20 volts, provides about one watt of drive to a single 

BLF245 MOSFET amplifier. The BLF245 stage operates from a supply voltage of 

28 volts in the FM30. 

The circuit board has components for input and output coupling and for power 

supply filtering. 


4.11 RF Driver (FM100/FM250) 

The RF Driver assembly is mounted on a 100 mm x 100 mm plate in the under side 

of the chassis. The driver amplifies the approximate 20 milliwatts from the 

frequency synthesizer to about 8 watts to drive the RF power amplifier. An 

MHW6342T hybrid, high-gain, wideband amplifier, operating at about 20 volts, 

provides about one watt of drive to a single BLF245 MOSFET amplifier. The 

BLF245 stage operates from a supply voltage of approximately 20 volts. 

The circuit board provides for input/output coupling and for power supply filtering. 

4.12 RF Amplifier (FM100/FM250) 

The RF power amplifier assembly is mounted on back of the chassis with four 

screws, located behind an outer cover plate. Access the connections to the module 

by removing the bottom cover of the unit. The RF connections to the amplifier are 

BNC for the input and output. Power comes into the module through a 5–pin 

header connection next to the RF input jack. 

The amplifier is built around a Phillips BLF278, a dual power MOSFET rated for 50 

volts DC and a maximum power of about 300 watts. When biased for class B, the 

transistor has a power gain of about 20 dB. (It is biased below class B in the 

transmitter.) 

Input transformer, T1111, is made up of two printed circuit boards. The four-turn 

primary board is separated from the one-turn secondary by a thin dielectric film. 

R1112–R1117 are for damping. Trim pot R1111 sets the bias. 

Output transformer, T1121, has a one-turn primary on top of the circuit board and a 

two-turn secondary underneath. Inductors L1121 and L1122 provide power line 

filtering. 


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4.13 Chassis 

The AC power supply components, as well as the bridge rectifier and main filter 

capacitor are mounted on the chassis. Switching in the power-entry module 

configures the power transformer for 100, 120, 220, or 240 VAC; see section 2.2 for 

switching and fuse information. A terminal strip with MOV voltage-surge 

suppressors and in-rush current limiters is mounted on the chassis between the 

power entry module and the toroidal power transformer. 

WARNING 

Shock hazard! 

Do not attempt to short the capacitor 

terminals. A bleeder resistor will 

discharge the capacitor in 

approximately one minute after 

shutdown. 

The main energy-storage/filter capacitor, C1001, is located between the voltage and 

power regulator boards. The DC voltage across the capacitor will be 45–55 volts 

(FM30 and FM100) or 65–70 volts (FM250) when the carrier is on. 

4.14 RF Output Filter & Reflectometer 

The RF low-pass filter/reflectometer are located in the right-hand compartment on 

the top of the chassis. See Illustration 6–14 and accompanying schematic for 

more information. 

A ninth-order, elliptic, low-pass filter attenuates harmonics generated in the power 

amplifier. The capacitors for the filter are circuit board pads. 

The reflectometer uses printed circuit board traces for micro-strip transmission 

lines. Transmission line segments (with an impedance of about 82 ohms) on 

either side of a 50–ohm conductor provide sample voltages representative of the 

square root of forward and reverse power. 

DC voltages, representative of forward and reflected power, go through a bulkhead 

filter board to the motherboard, then to the metering board, where they are 

processed for power control and metering and for SWR metering and protection. 


4.15 Receiver Circuit Board Option 

This option allows the transmitter to be used as a translator. The receiver board 

receives terrestrially fed RF signal and converts it to composite audio which is then 

fed into the exciter board. Microprocessor controlled phase lock loop technology 

ensures the received frequency will not drift, and multiple IF stages ensure high 

adjacent channel rejection. Refer to illustrations 4–6, 6–16 and its schematic for 

the following discussion. 

The square shaped metal can located on the left side of the receiver board is the 

tuner module. The incoming RF signal enters through the BNC connector (top 

left corner) and is tuned through the tuner module. Input attenuation is possible 

with jumper J1 on the top left corner of the receiver board. Very strong signals 

can be attenuated 20 dB automatically by placing the jumper on the left two pins 

(“LO” position). An additional 20 dB attenuation is also available with the jumpers 

in the top left corner of the board. The frequencies are tuned by setting switches 

SW1 and SW2 (upper right corner). These two switches are read upon power up 

by the microprocessor (U4). The microprocessor then tunes the synthesizer IC 

MC145170 (U3) to the selected frequency. The switches frequency range is 87.9 

Mhz at setting “00” to 107.9 Mhz at setting “64”. Other custom ranges are available. 

The synthesizer chip works on a phase lock loop system. It receives the frequency 

information from pin 6 of the tuner module, then goes through a FET buffer 

amplifier (Q2) on its way to synthesizer IC (U3). The synthesizer feeds back a DC 

voltage through two resistors to pin 4 of the tuner module. Different frequencies 

cause different tuning voltages to go to the tuner module to tune it on frequency. 

The frequency synthesizer locks on to the exact frequency needed and adjusts the 

DC voltage accordingly. The microprocessor tunes the frequencies of the 

synthesizer IC, but the DC tuning voltage is somewhat dependent on the tuner 

module. 

Generally, the voltage is around 0.5 volt DC for tuning 88.1 MHz, and from 5.5 to 

6.5 volts DC for tuning 107.9 MHz. The 10.7 MHz IF frequency comes out of the 

tuner module on pin 5 and is coupled into the first filter FL1; passes through FL1 

RF In 

Receiver 

Module 

® 

FM250 

Illustration 4–6 Receiver Board 


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and into the IF decoder system of IC LM1865 (U1). The FL1 filter sets the 

bandwidth or everything outside of the bandwidth depending on the filter that is 

selected. It could be a bandwidth of 180 kHz where everything outside of that is 

filtered out depending on the filter characteristics. A second filter (F3) is available 

when the signal has a great amount of interference from an adjacent signal. In 

such a case, remove the jumper cap that is in the F3 position, then remove the 

ceramic filter that is in the F4 storage position and place it into the F3 position. 

Then the signal goes to a buffer gain stage at pin 1 of LM1865 (U1). From there 

the signal passes through F2, which is a second filter for further removal of 

unwanted products, and then it goes on to the IF of that chip. The quadrature coil 

L4 is tuned to 10.7 MHz as per calibration procedures. This results in a low 

distortion of around 0.2 to 0.3% on the audio. The audio, still a composite at this 

point, will come out of pin 15 of that IC (U1) and go to the first buffer U9. Then it 

goes through a compensation network R54 and C26, and on to the stereo decoder 

chip at pin 2 of U5. 

When a stereo signal is present, Led 1 illuminates which indicates that left and 

right audio is available. Then the stereo signals go to gain stages U6A and U6B and 

out to the RCA jacks on the back of the cabinet. These can be used for off-air 

monitoring of the audio signal. Incoming frequency can be monitored from the 

frequency monitor BNC jack on the back. The stereo buffer U9, stereo decoder U5, 

and gain stages U6A and U6B have no effect on the signal that goes through the 

transmitter. This section along with the composite signal coming out of pin 15 of 

LM1865 (U1) is totally separate from the transmitter section. 

A muting circuit, consisting of C22, a 1N914 diode, R14, and varible resistor R15 

mutes the output when a signal is too weak to be understood. The strength of the 

signal muted is determined by the adjustment of R15. Any signal below the setting 

of R15 is shorted to +VCC through C22 by the current drawn through R14 and the 

diode. The audio signal above this setting goes through C17 to the connector P3. 

The P3 connector block allows jumpering to either internal circuitry or to external 

signal processing such as advertisement injection or other forms of altering the 

signal. If the jumper is installed for internal circuitry, the signal will go through 

R39 to the input of U2A. This is a buffer that drives the R20 pot located on the top 

left hand corner of the board. R20 sets signal gain for 100% modulation if 

adjusted correctly with a full incoming 75 kHz deviation signal. Then the signal 

goes through R21, R22, and C20 which, along with adjustable pot R24 and C21, 

forms a compensation network with some phase shifting. This allows the best 

stereo separation possible by adjusting and compensating for differences in FM 

exciter boards. The signal is buffered through U2B and finally reaches the output 

connectors P1 and P2, and on to the transmit circuitry. 

The power supply is fairly straight forward. The incoming 12 volt supply goes to a 

7809, 9 volt regulator (VR1) which supplies all 9–volt needs on the board. The 9 

volts also supplies a 7805, 5 volt regulator (VR2) which supplies all 5–volt needs on 

the board. Plus and minus 12 volts from the motherboard is filtered and supplies 

various needs on the board. Finally there is a precision reference voltage supplied 

through R50 by U7 and U8. These two 2.5 volt reference shunts act very much like 

a very accurate zenor diode to provide precision 5 volts to the metering board. 


Section 5—Adjustments and Tests 

This section describes procedures for (1) advanced users who 

may be interested in customizing or optimizing the performance 

of the transmitter and (2) service personnel who want to return 

the transmitter to operational status following a maintenance 

procedure. 

Adjustments and Tests 

5–1

5.1 Audio Processor Adjustments 

5.1.1 Pre-Emphasis Selection 

Select the pre-emphasis curve (75 µsec, 50 µsec, 25 µsec, or Flat) by jumpering the 

appropriate pins of header JP1 on the audio processor board. (See section 2.9.) If 

you change the pre-emphasis, change the de-emphasis jumpers, JP203 and JP204 

on the Stereo Generator board, to match. (See section 2.8.) 

5.1.2 Pre-Emphasis Fine Adjustment 

Trim potentiometers, R29 and R65, (for left and right channels, respectively) 

provide for fine adjustment of the pre-emphasis. Set the potentiometers to bring 

the de-emphasized gain at 10 kHz equal to that of 400 Hz. (At the proper setting, 

15.0 kHz will be down about 0.7 dB.) 

When making these adjustments, it is important that you keep signal levels below 

the processor gain-control threshold. 

A preferred method is to use a precision de-emphasis network in front of the audio 

input. Then, use the non-de-emphasized (flat) output from the FM modulation 

monitor for measurements. 

5.2 Stereo Generator Adjustments 

5.2.1 Separation 

Feed a 400–Hz sine wave into one channel for at least 70% modulation. Observe 

the classic single-channel composite stereo waveform at TP301 on the RF Exciter 

circuit board. Adjust the Separation control for a straight centerline. 

Since proper adjustment of this control coincides with best stereo separation, use 

an FM monitor to make or confirm the adjustment. 

5.2.2 Composite Output 

You can make adjustments to the composite output in the following manner: 

❑ 

Using a modulation monitor 


Using a Modulation Monitor 

1. Set the Stereo-Mono switch to Mono. 

2. Check that the setting of the Modulation compensation control (see illustration 

2–6) on the RF Exciter circuit board, falls within the range specified for 

the frequency of operation. (See section 2.3.1.) 

3. Feed a sine wave signal of about 2.5 kHz into the left channel at a level 

sufficient to put the wideband gain-reduction indicator somewhere in the 

middle of its range. 

4. Set the Composite level control to produce 90% modulation as indicated on 

an FM monitor. 

5. Apply pink noise or program material to the audio inputs and confirm, on 

both Mono and Stereo, that modulation peaks are between 95% and 100%. 


5–3

5.2.3 19–kHz Level 

Adjust the 19–kHz pilot for 9% modulation as indicated on an FM modulation 

monitor. 

(The composite output should be set first, since it follows the 19–kHz Level 

control.) 

5.2.4 19–kHz Phase 

1. Apply a 400–Hz audio signal to the left channel for at least 70% modulation. 

2. Look at the composite stereo signal at TP301 on the RF Exciter circuit board 

with an oscilloscope, expanding the display to view the 19–kHz component 

on the horizontal centerline. 

3. Switch the audio to the right-channel input. When the 19–kHz Phase is 

properly adjusted, the amplitude of the 19–kHz will remain constant when 

switching between left and right. 

4. Recheck the separation adjustment as described in section 5.2.1. 

5.3 Frequency Synthesizer Adjustments 

5.3.1 Frequency (Channel) Selection 

Refer to section 2.3. 

5.3.2 Modulation Compensator 

Refer to section 2.3. 

5.3.3 Frequency Measurement and Adjustment 

Next to the 10.24–MHz crystal on the RF Exciter board is a 5.5–18 pF ceramic 

trimmer capacitor (C307). Use C307 to set the frequency of the 10.24–MHz crystal 

while observing the output frequency of the synthesizer. 

Use one of two methods for checking frequency: 

❑ 

❑ 

Use an FM frequency monitor. 

Couple a frequency counter of known accuracy to the output of the synthesizer 

and observe the operating frequency. 


5.3.4 FSK Balance Control 

An FSK signal (used for automatic identification of FM repeaters) shifts the 

frequencies of the 10.24–MHz crystal reference oscillator and the VCO. 

Use an oscilloscope to observe the cathode end of D306. With no program, the 

pulse will be less than 1 µsec wide. With an FSK input (a 20–Hz square wave at 

the FSK input will work), set trim pot R345 for minimum pulse width. 

The setting will vary slightly with operating frequency. 

5.4 Metering Board Adjustments 

5.4.1 Power Calibrate 

While looking at RF Power on the digital panel meter, set the Power Calibrate trim 

potentiometer to agree with an external RF power meter. 

5.4.2 Power Set 

With the front panel RF Output control fully clockwise, adjust the Power Set trim 

pot to 10% more than the rated power (33 W for FM30, 110 W for FM100, 275 W 

for FM250) as indicated on an accurate external watt meter. If the authorized 

power is less than the maximum watts, you may use the Power Set to limit the 

range of the RF Output control. 

5.4.3 SWR Calibrate 

When the Carrier switch is off, or the RF power is less than about 5 watts, the 

SWR circuit automatically switches to a calibrate-check mode. (See section 4.5 for 

more information.) 

Set the digital panel meter to read SWR. With the Carrier switch off, set the SWR 

CAL trim pot to read 1.03. 


5–5

5.4.4 PA Current Limit 

Since it may not be practical to increase the PA current to set the PA Current 

Limit control, you may use this indirect method. 

With the carrier turned off, look at the DC voltage at the right end of R413 on the 

Metering board. The current limit, in amperes, will be 0.35 amps higher than ten 

times this voltage. For example, for a current limit of 7.35 amps, adjust the PA 

Current Limit control for 0.7 volts at R413 ; or 0.565 volts for 6.0 amps. Set the 

current limit for 3 amps (FM30), 6 amps (FM100), or 8.5 amps (FM250). 

5.5 Motherboard Adjustments 

See page 6-14 for motherboard jumper configuration. 

5.6 Display Modulation Calibration 

The Modulation Calibrate trim pot sets the sensitivity of the front panel 

Modulation bar graph display. 

This adjustment may be made only after the Output trim pot on the Stereo 

Generator board has been set. (See section 5.2.4.) 

1. Set the Stereo-Mono switch to Mono. 

2. Feed a sine wave source of about 2.5 kHz into the left channel at a level 

sufficient to put the wideband gain-reduction indicator somewhere in the 

middle of its range. 

3. Set the Modulation Calibrate trim pot so that the “90” light on the front 

panel Modulation display just begins to light. 

5.7 Voltage Regulator Adjustments 

JP701, a 10–pin header on the Voltage Regulator board, sets the time between 

program failure and carrier turnoff. Pins 1 and 2 are the two pins closest to the 

edge of the board. The times are approximate. Sections 2.11, 2.12, and 4.8 

contain further information. 

1. Short pins 1 and 2 for a 30–second delay. 

2. Short pins 3 and 4 for a 2–minute delay. 

3. Short pins 5 and 6 for a 4–minute delay. 

4. Short pins 7 and 8 for an 8–minute delay. 

You may select other times by changing the value of R721. The time is 

proportional to the resistance. 


5.8 Bias Set (RF Power Amplifier) 

The Bias Set trim pot is located inside the PA module on the input circuit board. 

Set the trim pot to its midpoint for near-optimum bias. 

5.9 Performance Verification 

Measure the following parameters to receive a comprehensive characterization of 

transmitter performance: 

❑ Carrier frequency 

❑ RF output power 

❑ RF bandwidth and RF harmonics (see section 5.12) 

❑ Pilot frequency, phase, and modulation percentage 

❑ Audio frequency response 

❑ Audio distortion 

❑ Modulation percentage 

❑ FM and AM noise 

❑ Stereo separation between left and right 

❑ Crosstalk between main channel and subcarrier 

❑ 38–kHz subcarrier suppression 

In addition to the above tests, which pertain to signal quality, a complete check of 

the unit will include items listed in section 5.21. 

5.9.1 Audio Proof-of-Performance Measurements 

References to “100%” modulation assume 9% pilot and 91% for the remainder of 

the composite stereo signal. 

Because the audio processing threshold is at 90% modulation, it is not possible to 

make audio proof-of-performance measurements at 100% modulation through the 

audio processor. Instead, data is taken at a level below the audio processing 

threshold at 80% modulation. 

5.9.2 De-emphasis Input Network 

A precision de-emphasis network, connected between the test oscillator and the 

audio input of the transmitter, can be very helpful when making the audio 

measurements. Note that the input impedance of the transmitter or the source 

impedance of the test oscillator can affect network accuracy. With the de-emphasis 

network, oscillator level adjustments need only accommodate gain errors, instead 

of the whole pre-emphasis curve. 


5–7

5.10 Carrier Frequency 

Carrier frequency is measured at the output frequency with a frequency monitor 

or suitable frequency counter. 

To adjust frequency, see section 5.3.3. (FCC tolerance +/– 2000 Hz per FCC Part 

73.1540 and 73.1545.) 

5.11 Output Power 

The output power reading on the front panel display should be 90–105% of the 

actual value. For a more precise measurement, use a watt meter in the RF output 

line. See sections 5.4.1 and 5.4.2 for setting power. 

5.12 RF Bandwidth and RF Harmonics 

You can observe RF bandwidth and spurious emissions with an RF spectrum 

analyzer. 

In the Stereo mode, feed a 15.0–kHz audio signal into one channel to provide 85% 

modulation as indicated on a monitor. Doing so produces 38% main, 38% stereo 

subcarrier, and 9% pilot per FCC Part 2.1049. As an alternative, use pink noise 

into one channel. 

Using a spectrum analyzer, verify the following (per FCC 73.317): 

1. Emissions more than 600 kHz from the carrier are at least 43 + 10log(power, 

in watts) dB down (58 dB for 30 watts, 63 dB for 100 watts, 67 dB for 250 

watts). The scan should include the tenth harmonic. 

2. Emissions between 240 kHz and 600 kHz from the carrier are down at least 

35 dB. 

3. Emissions between 120 kHz and 240 kHz from the carrier are down at least 

25 dB. 

5.13 Pilot Frequency 

The pilot frequency should be within 2 Hz of 19 kHz. (FCC Part 73.322.) Using a 

frequency counter, measure 1.9 MHz at pin 1 of U209 on the Stereo Generator 

board. A 200–Hz error here corresponds to a 2–Hz error at 19 kHz. If the 

frequency is off by more than 50 Hz, you may change the value of C213. (Changing 

C213 from 56 pF to 68 pF lowers the 1.9 MHz by about 35 Hz.) 


5.14 Audio Frequency Response 

For the response tests, take the readings from an FM modulation monitor. 

Make audio frequency response measurements for left and right channels at 

frequencies of 50 Hz, 100 Hz, 400 Hz, 1 kHz, 5 kHz, 10 kHz, and 15 kHz. See 

sections 5.9.1 and 5.9.2. 

5.15 Audio Distortion 

Make distortion measurements from the de-emphasized output of an FM 

modulation monitor. 

Make audio distortion measurements for left and right channels at frequencies of 

50 Hz, 100 Hz, 400 Hz, 1 kHz, 5 kHz, 10 kHz, and 15 kHz. See sections 5.9.1 and 

5.9.2. 

5.16 Modulation Percentage 

While feeding an audio signal into the left channel only, confirm that the total 

modulation percentage remains constant when switching between Mono and 

Stereo. 

Measure modulation percentage with an FM modulation monitor. 

See section 5.2.2. 

19–kHz pilot modulation should be 9%. 

5.17 FM and AM Noise 

Take noise readings from a de-emphasized output of a modulation monitor. 

5.18 Stereo Separation 

Make left-into-right and right-into-left stereo separation measurements with an 

FM modulation monitor for frequencies of 50 Hz, 100 Hz, 400 Hz, 1 kHz, 5 kHz, 

10 kHz, and 15 kHz. 

5.19 Crosstalk 

For stereo crosstalk measurements, both left and right channels are fed at the 

same time. For best results, there needs to be a means of correcting small 

imbalances in levels and phase. The balance is made at 400 Hz. 


5–9

5.19.1 Main Channel Into Sub 

Feed the left and right channels in phase with audio (L+R) at 50 Hz, 100 Hz, 400 

Hz, 1 kHz, 5 kHz, 10 kHz, and 15 kHz at 100% modulation, while observing the 

stereo subcarrier (L-R) level on an FM modulation monitor. 

5.19.2 Sub Channel Into Main 

Feed the audio into the left and right channel as above, with the exception of 

reversing the polarity of the audio of one channel (L-R input). Using the 

frequencies of 5.19.1 above, observe the main channel (L+R) level with a 

modulation monitor. 

5.20 38–kHz Subcarrier Suppression 

With no modulation, but in the Stereo mode, the 38–kHz subcarrier, as indicated 

on an FM modulation monitor, should be down at least 40 dB. 

5.21 Additional Checks 

In addition to the tests and adjustments mentioned in this section, the following 

checks ensure a complete performance appraisal of the transmitter: 

1. Perform a physical inspection, looking for visible damage and checking that 

the chassis hardware and circuit boards are secure. 

2. Check the functionality of switches and processing control. 

3. Verify that all indicators function. 

4. Check the frequency synthesizer lock at 80 MHz and 110 MHz. 

5. Measure the AC line current with and without the carrier on. 

6. Perform a functional test of the SCA input, Monitor outputs, and the monitor 

and control function at the 15–pin, D-sub connector. 

7. Test the functionality of the FSK circuit. 

8. Check the operation and timing of the automatic carrier-off circuitry associated 

with program failure. 

9. Check all metering functions. 

10. Test ALC action with PA current overload, SWR, and PLL lock. 

NOTE: 

FCC type acceptance procedures call for testing the carrier frequency over the 

temperature range of 0–50 degrees centigrade, and at line voltages from 85% to 

115% of rating. (See FCC Part 2.1055.) 


Section 6—Reference Drawings 

The illustrations in this section may be useful for making adjustments, 

taking measurements, troubleshooting, or understanding 

the circuitry of your transmitter. 

Reference Drawings 

6–1

6.1 Views 

Gain 

Reduction/Expansion 

Indicators 

Digital Multimeter 

Multimeter Select 

Modulation 

Indicators 

Carrier Switch 

Audio Input 

High 

-6 

-12 

2 

10 

High Band 

Expand Compress 

2 

20 

Wide Band 

+6 dB +12 dB 

RF Power 

SWR 

ALC 

PA DC Volts 

PA DC Amps 

PA Temperature 

Supply DC Volts 

Voltmeter 

Fault 

SWR 

Lock 

Input 

PA DC 

PA Temp 

Stereo 

Modulation 

Over 

100 

90 

80 

70 

60 

50 

40 

30 

Carrier 

Power 

-18 

20 

Low 

Input Gain 

Processing 

Mono 

RF Output 

Pilot 

FM BROADCAST TRANSMITTER 

Audio Processor Processing Control 

Input Level 

Indicators Input Gain 

Switches 

Stereo/Mono Relative RF 

Switch Voltage Out 

Fault Indicators 

Power Switch 

Illustration 6–1 Front View 

RF Output 

RF Output Monitor 

Composite 

Input 

Audio Monitors 

Audio Inputs 


RIGHT 

LEFT/MONO 

R 

L 

REMOTE I/O 

1 

2 3 

FUSE 

CIRCUIT 

BREAKER 

OFF 

+ 

B 

A 

T 

T 

E 

R 

Y 

36 VDC 

AC Power In 

SCA Inputs 

Power Amplifier 

Remote I/O 

and Cooling 

(FM100 and FM 250 only) 

DC Circuit 

Breaker 

DC Power In 

Illustration 6–2 Rear View 


6.2 Board Layouts and Schematics 

Illustration 6–5 Audio Processor Board 


L VU 

L IN1 

L IN2 

/+12DB 

/+6DB 

R VU 

R IN1 

R IN2 

+12V 

R2 

1K 

C1 

100PF 

R3 

1K 

C2 

100PF 

R10 

47K 

R40 

1K 

C13 

100PF 

R41 

1K 

C14 

100PF 

+5V 

C40 

1.0 

C3 

1.0 

C4 

1.0 

R11 

47K 

C15 

1.0 

C16 

1.0 

R4 

24.9K 

1 

R5 

24.9K 

1 

R7 

24.9K 

1 

1K 

R42 

24.9K 

R43 

24.9K 

R45 

24.9K 

+5V 

-5V 

R48 

R6 

24.9K 

1 

+12V 

8 

2 

3 

-12V 

4 

R44 

24.9K 

+12V 

8 

2 

3 

-12V 

2 

IN VO 6 

U17 

4 

GND 

C42 

0.1 

REF02 

TRM 

5 

C44 

0.1 

4 

R9 1K 

1 

U1A 

TL072 

16 

7 

8 

1 

U2A 

TL072 

+12V 

R8 

30.1K 

1 

R12 

20K 1 

13 

3 

X 

Y 

R49 

20K 1 

R47 

30.1K 

1 

2 

3 

U3 

X0 

X1 

X2 

X3 

Y0 

Y1 

Y2 

Y3 

INH 

A 

B 

74HC4052 

+12V 

-12V 

R118 

10.0K 

1 

6 

5 

8 

4 

U18B 

TL072 

1 

U18A 

TL072 

C37 

.01 

7 

6 

5 

6 

5 

12 

14 

15 

11 

1 

5 

2 

4 

6 

10 

9 

U1B 

TL072 

7 

7 

U2B 

TL072 

C36 

.01 

R119 

4.7K 

R120 

100 

R121 

10.0K 1 

R122 

100 

L LP2 

L LP1 

R13 

2.0K 

1 

R14 

1.0K 

1 

R15 

499 

1 

R16 

499 

1 

R51 

1.0K 

1 

R52 

499 

1 

R1 

100 

R LP2 

R LP1 

R50 

2.0K 

1 

R53 

499 

1 

R98 

100 

+5V 

C38 

1.0 

C39 

1.0 

-5V 

C5 

.047 

C17 

.047 

+5.00V 

C6 

.047 

C46 

0.1 

C48 

0.1 

R20 

75K 

1 

R56 

75K 

1 

C18 

.047 

R46 

360K 

6 

5 

R17 

360K 

GAIN REDUCTION VOLTS P-P 

THRESHOLD 1.1 

10DB 3.5 

20DB 11 

U4B 

TL072 

7 

+12V 

U4A 

8 

2 

TL072 

1 

3 

4 

-12V 

VEE 

VSS 

-5V 

C47 

0.1 

VDD 

+5V 

7 

7 

9 

13 

12 

7 

9 

13 

12 

+12V 

-12V 

C50 

47PF 

-5VDC at 0DB GR 

4.1V at 20 DB GR 

R78 

91K 

+12V 

11 

U5 

AD632 

14 

1 

-12V 

3 

14 

AD632 

1 

2 

U6 

10 

11 3 

+5V 

Q5 

LM394 

8 

1 

8 C1 

7 

2 

7 B2 

6 

3 

6 E3 

5 

4 

5 4 

D20 

R80 

3.3K 

R79 

49.9K 

1 

10 

2 

R59 

100K 1 

3mV/DB 

R82 

120 

R58 

11.3K 

1 

R23 

100K 1 

C20 

1.0 

POLY 

R123 

50K 

R22 

11.3K 

1 

C8 

1.0 

POLY 

1 

2 

3 

SW1A 

R83 

10K 

C28 

1.0 

POLY 

D13 

C27 

.047 

R24 

24.9K 

1 

6 

5 

(+/-5.0V PK) 

R60 

24.9K 

R61 

24.9K 

2 

3 

R25 

24.9K 

1 

+12V 

(+/-5.0V PK) 

8 

U7A 

D1 

7 

U7B 

TL072 

D8 

D7 

1 

D2 

TL072 

4 

-12V 

R87 

3.3K 

D19 

SW1B 

5 

1 

U13A 

TL072 

R85 

0 

R89 

330K 

R86 

3.3M 

4 

6 

C26 

100PF 

D14 

YEL 

+12V 

8 

2 

3 

-12V 

4 

GAIN: U5, Pin 2 to U8, Pin 2 

(No Hi-band gain reduction) 

FLAT A=0 

25uSEC A=0.33 

50uSEC A=0.67 

75uSEC A=1.0 

R26 

100K 

Q1 

2N5087 

R88 

10M 

R91 

10M 

D15 

R75 

2.4K 

R28 

OPEN 

PRE-EMP. 

R62 

100K 

R64 

OPEN 

PRE-EMP. 

R65 

10K 

Q2 

2N5087 

R92 

-5V 

PROC A 

PROC B 

PROC C 

1K 

C30 

1.0 

R90 

1K 

C29 

0.1 

Q3 

2N5210 

R29 

10K 

R30 

49.9K 

1 

R66 

49.9K 

1 

HEAVY 

LIGHT 

POT LOCATED 

ON DISPLAY PCB 

R93 

10K 

R650 

100K 

FLAT 

25uS 

50uS 

75uS 

R76 

10K 

R77 

3.3K 

7 

9 

13 

12 

7 

9 

13 

12 

TEST 

+12V 

11 

-12V 

+12V 

11 

-12V 

C49 

47PF 

14 

AD632 

U8 

3 

14 

AD632 

U9 

JP1 

HEADER 4X2 

1 2 

3 4 

5 6 

7 8 

3 

1 

2 

10 

1 

2 

10 

R31 

24.9K 

1 

R67 

24.9K 

+5V 

R94 

20.0K 

1 

R95 

20.0K 

1 

C10 

.0027 

POLY 

R32 

12K 

R33 

10K 

C22 

.0027 

POLY 

R68 

12K 

R69 

10K 

R96 

20.0K 

1 

Q7 

LM394 

1 

1 C 

8 

8 

2 

2 B 

7 

7 

3 

3 E 

6 

6 

4 

5 

4 5 

D21 

R99 

3.3K 

R39 

1K 

R81 

1K 

R97 

49.9K 

1 

3mV/DB 

R34 

24.9K 1 

6 

5 

C11 

220PF 

U10B 

TL072 

R70 

24.9K 

C23 

220PF 

-12V 

7 

+12V 

8 

2 

1 

3 

U10A 

4 TL072 

R100 

120 

R101 

10K 

.25V/DB 

C12 

0.1 

C24 

0.1 

R72 

24.9K 

D16 

R36 

24.9K 

D11 

D5 

R35 

240K 

C33 

.047 

R71 

240K 

C34 

OPEN 

R73 

24.9K 

-12V 

R38 

1K 

R37 

24.9K 

6 

5 

R74 

1K 

D12 

D6 

+12V 

8 

U12A 

2 TL072 

1 

3 

1 

4 

U14A 

TL072 

C32 

100PF 

D17 

U12B 

TL072 

7 

+12V 

8 

2 

3 

-12V 

R103 

0 

R104 

OPEN 

4 

R109 

3.3K 

R105 

1M 

R106 

1K 

D18 

560 

C35 

1.0 

+5V 

-5V 

+5V 

-5V 

D3 

D4 

D9 

D10 

R107 

10K 

L OUT 

R OUT 

-12V 

C41 

1.0 

C43 

0.1 

J1 

C45 

0.1 

1 2 

3 4 

5 6 

7 8 

9 10 

11 12 

13 14 

15 16 

17 18 

19 20 

RECEPT 10X2 

-12V 

L IN1 

L IN2 

R IN1 

R IN2 

L LP1 

L LP2 

R LP1 

R LP2 

R OUT 

L OUT 

C8A 

OPEN 

10 

8 

6 

4 

2 

J2 

RECEPT 5X2 

C20A 

OPEN 

9 

7 

5 

3 

1 

J3 

1 2 

3 4 

5 6 

7 8 

9 10 

11 12 

13 14 

15 16 

17 18 

19 20 

21 22 

23 24 

25 26 

RECEPT 13X2 

+12V 

-12V 

/+6DB 

/+12DB 

L VU 

R VU 

+5.00V 

PROC A 

PROC B 

PROC C 

BR GR 

HI GR 

TEST 

7 

U13B 

TL072 

C25 

100PF 

6 

5 

6 

5 

U15B 

TL072 

7 

R111 

49.9K 

1 

R84 

49.9K 

1 

R110 

49.9K 

1 

2 

3 

R112 

49.9K 

1 

+12V 

8 

1 

4 U15A 

TL072 

-12V 

R113 

100 

.25V / DB 

BR GR 

C31 

100PF 

7 

U14B 

TL072 

NOTES : 

1. ALL RESISTORS ARE IN OHMS, 1/4W, 5% UNLESS OTHERWISE SPECIFIED. 

2. ALL CAPACITORS ARE IN MICROFARADS UNLESS OTHERWISE SPECIFIED. 

3. ALL DIODES ARE 1N4148 UNLESS OTHERWISE SPECIFIED. 

6 

5 

6 

5 

7 

U16B 

TL072 

R115 

49.9K 

1 

R102 

49.9K 

1 

R114 

49.9K 

1 

R116 

49.9K 

1 

+12V 

8 

2 

3 

1 

4 U16A 

TL072 

-12V 

R117 

100 

0.25V / DB 

SCM, FM Audio AUDIO Processor PROCESSOR 

103202 

-5V 

HI GR 


6–5

Illustration 6–6 Stereo Generator Board 


EXT RTN 

R54 24.9K 1% 

+12V 

R55 24.9K 

EXTERNAL COMPOSIT IN 

(3.5V P-P for 75KHz) 

EXT IN 

R56 

24.9K 1% 

R57 

2 

3 

8 

4 

C26 

1.0 

1 

U6A 

TL072 

R58 

3.9K 

D3 

D4 

24.9K 

C13 

56PF 

NPO 

R26 

1K 

Y1 

7.6MHZ 

CLK 

QA 

QB 

QC 

QA XOR QC 

QB XOR QC 

Current at U211 pin 4. 

QD 

QB XOR QD 

C12 

5.5—18PF 

LPIN L 

LPIN R 

C14 

33PF 

NPO 

+6V 

C24 

1.0 

R25 

1M 

1 2 

U7A 

74HC04 

D1 

1N5818 

15.2 KHz LOW-PASS FILTER 

(8th ORDER ELLIPTICAL) 

LTC1064-1 

1 

14 

2 

13 

3 

12 

4 U1 11 

5 

10 

6 

9 

7 

8 

U7F 

14 

13 12 

7.6 MHz 

7 

1 

2 

3 

4 

5 

6 

7 

LTC1064-1 

U2 

C29 

1.0 

14 

13 

12 

11 

10 

9 

8 

1 

4 

2 

+6V 

C23 

1.0 

R27 

100 

U8A 

74HC390 

CK 

CK 

CLR 

-6V 

C? 

100 pF 

C? 

100 pF 

D2 

1N5818 

3 

Q 

5 

Q 

6 

QC 

7 

QD 

R1 

330 

R2 

330 

1.52 MHz 

15 

12 

14 

CK 

CK 

CLR 

U8B 

74HC390 

U7B 

74HC04 

3 4 

U7C 

74HC04 

5 6 

U7D 

74HC04 

9 8 

3 

4 

5 

6 

16 

8 

C1 

.0027 

POLY 

C2 

.0027 

POLY 

U9A 

74HC393 

QA 

QB 

QC 

QD 

QA 

QB 

QC 

QD 

A 

CLR 

LPOUT L 

LPOUT R 

13 

11 

10 

9 

304 Khz 

1 

2 

U9B 

74HC393 

13 

12 

INPUT L 

INPUT R 

A 

CLR 

14 

Q 

Q 

QC 

QD 

7 

11 

10 

9 

8 

1 

R38 

1M 

1 

R39 

1M 

JP1 

2 

JP2 

2 

3 

3 

+5.00V 

R6 

499 

1% 

R18 

499 

1% 

74HC86 

1 

2 

4 

5 

U10A 

U10B 

14 

3 

6 

C5 

.0027 

POLY 

R7 

3.65K 

1% 

C30 

1.0 

3.8 MHz 

C6 

1030PF 

C9 

.0027 POLY 

R19 

3.65K 1% 

C10 

1030PF 

R28 

243K 1% 

R29 

100K 1% 

VR1 

+12V 

LM317 

+12V 1 

+6V 

-6V 

IN 

OUT 3 

C33 

C 

C34 

1.0UF 

R49 

2 

240 

1.0UF 

EXTERNAL COMPOSITE 

R50 

910 

9 

10 

12 

13 

74HC86 

U10C 

U10D 

7 

8 

11 

1.9MHz 

R30 

243K 

1% 

R31 

100K 

1% 

+12V 

8 

2 

3 

4 

6 

5 

-12V 

U3B 

TL072 

C15 

0.1 

1 

7 

C 

L 

K 

A 

C 

L 

K 

B 

C16 0.1 

1 

0 

1 

U3A 

TL072 

L 

S 

H 

5 

0 

/ 

1 

0 

9 

1 

2 

V 

D 

+ 

V 

D 

- 

R8 

4.99K 1% 

R20 

4.99K 

1% 

8 

1 

3 

+6V 

V 

A 

+ 

V 

A 

- 

7 

1 

4 

S 

A 

/ 

B 

A 

G 

N 

D 

6 

1 

5 

S 

1 

A 

S 

1 

B 

(3.5V P-P for 7.5KHz) 

SCA IN 

5 

1 

6 

1 

3 

JP3 

2 

50 75 

C7 

.01 POLY 

1 

3 

2 

50 75 

C31 

1.0 

I 

N 

V 

A 

I 

N 

V 

B 

R33 

10.0K 1% 

4 

1 

7 

C32 

1.0 

R10 

2.49K 1% 

R22 

2.49K 

1% 

H 

P 

A 

H 

P 

B 

3 

1 

8 

R35 

10.0K 1% 

C11 

.01 POLY 

B 

P 

A 

B 

P 

B 

2 

1 

9 

JP4 

1 

L 

P 

A 

L 

P 

B 

2 

0 

R34 

49.9K 

1% 

R36 

49.9K 

1% 

6 

5 

U11 

LMF100 

+12V 

2 

3 

R204 

1K 

U205 Connections 

8 

-12V 

U4B 

TL072 

1 

4 U4A 

TL072 

7 

C17 

0.1 R37 

1K 

C19 

0.1 

R3 

0 OHM 

C18 

.0027 

POLY 

R24 

100 

R11 

100 

SYNC OUT 

R41 

510 

38 KHz 

3.0VP-P 

MON R 

R40 

10K 

C21 

0.1 

C20 

.0027 

POLY 

-12V 

MON L 

C27 

1.0 

C3 

100PF 

R32 

10K 

19 KHZ PHASE 

MONO/STEREO 

/EXT ENABLE 

7 

9 

13 

12 

19 KHz 

3.3VP-P 

11 

R9 

2K 1% 

+12V 

14 

3 

-12V 

R53 

10K 

D6 

+6V 

U12 

B-B 4214 

C4 

0 OHM 

1 

2 

10 

R21 

10K 

U5 

74HC4053 

9 

R47 

20K 

12 

13 

2 

1 

5 

3 

6 

11 

10 

19 KHZ LEVEL 

R242 1K R244 10K 

D5 

NOTES : 

_______ 

_______ 

R46 

10K 

X0 

X1 

Y0 

Y1 

Z0 

Z1 

INH 

A 

B 

C 

+6V 

C37 

OPEN 

R48 

4.3K 

16 

8 7 

SEPARATION 

-6V 

R13 

24.9K 1% 

R23 

24.9K 1% 

R5 

1K 

R12 

10.0K 

1% 

X 

Y 

Z 

R43 

33K 

C28 

1.0 


2. ALL CAPACITORS ARE IN MICROFARADS UNLESSOTHERWISE SPECIFIED. 

3. ALL DIODES ARE 1N4148 UNLESS OTHERWISE SPECIFIED. 

CROWN INTERNATIONAL, INC. 

14 

15 

4 

OUTPUT 

R14 

6 

5 

1K 

-12V 

+12V 

J1 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

U6B 

TL072 

RECEPT 12X1 

J2 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

RECEPT 12X1 

1718 WEST MISHAWAKA ROAD ELKHART, IN. 46517 PHONE (219) 294-8000 

SCM, FM STEREO GENERATOR 

7 

R15 (SELECTABLE BY TEST, USE 

4.02K 4.12K OR 4.15K IF NEEDED) 

1% 

10 

8 

6 

4 

2 

J3 

9 

7 

5 

3 

1 

RECEPT 5X2 

GND 

R16 

100 

R17 

100 

EXT IN 

EXT RTN 

SCA IN 

COMP OUT 

COMP METER 

MONO/STEREO 

/EXT ENABLE 

GND 

INPUT L 

INPUT R 

MON L 

MON R 

LPIN L 

LPOUT L 

LPIN R 

LPOUT R 

+5.00V 

SYNC OUT 

COMP OUT 

(•3.85V P-P) 

COMP METER 

+5.00V 

QC XOR QD 

Current at U211 pin 17. 

U7E 

74HC04 

11 10 

VR2 

LM337 

-12V -6V 

-12V 

1 

3 

IN 

OUT 

C35 

1.0 

C 

2 

R52 

910 

R51 

240 

C36 

47UF 

STEREO 

MONO 

STEREO/MONO 

X 

B 

Y 

A 

U5Y 

U5X 

X1 

X0 

Y1 

Y0 

Z1 

Z0 

U5Z 

Z 

C 

U206, pin6 

/EXT EN 

DRAWN 

CHECKED 

SCALE 

PROJ # 

FILENAME: 

JFL 

JB 1 

103203A.SCM 

NONE 

7-28-97 

MLOWCM0 

ME 

EE 

PE 

APPROVED BY : 

NEXT ASM: 

SUPERSEDES 

E.C. 

DWG. NO. 

DO NOT SCALE PRINT 

103203 

REV 

A 

Stereo Generator 


6–7

SEE NOTE 10 

TOP SIDE COMPONENT MAP, FM-VFM EXCITER 

UNCONTROLLED 

UNLESS OTHERWISE MARKED IN RED BY CM AS A 

CONTROLLED COPY, COPIES OF THESE DOCUMENTS AND 

ASSOCIATED ELECTRONIC FILES ARE UNCONTROLLED AND 

ARE FOR REFERENCE ONLY. 

THESE DRAWINGS, SPECIFICATIONS AND ASSOCIATED 

ELECTRONIC FILES ARE THE PROPERTY OF INTERNATIONAL 

RADIO AND ELECTRONICS CORP., AND SHALL NOT BE REPRODUCED, 

COPIED, OR USED AS THE BASIS FOR THE MANUFACTURE OR SALE OF 

APPARATUS OR DEVICES WITHOUT PERMISSION. 

SIZE 

B 

DWG. NO. 

PWB: 200440-PWB-A.PCB 

200440-PWA 

M200440PT-A.DOC 

SCALE: N/A PROJECT #: 509 SHEET: 1 OF 1 

REV 

A

H 

1 2 3 4 5 6 DWG. NO. 

REV. 

8 9 10 11 12 

200440-SCH 

A 

REVISION HISTORY 

APPROVALS 

E . C . N. REV DESCRIPTION 

DATE DWN CHK CM PE 

1 FOR PROTOTYPE 01-04-02 DW 

2 MODIFIED PER MIKE SENEKI 

02-06-02 DW 

3 CHG'D R18 PER EAD MRH01. R18 WAS 91K OHM. U5 WAS C 6900-5 06-24-02 DW 

246 A-G 4 R8 WAS 1.0K OHM. 

05-23-03 DW 

277 A PRODUCTION RELEASE 

01-29-04 DW 

DW DP 

H 

+8V 

88-108 MHZ 

G 

F 

E 

D 

C 

B 

A 

HD1 

HEADER 5X2 

10 

C_L_SHT1_A.DOT REV. A 

RF OUT 

COMPOSITE IN 

-12V 

+5V 

GND 

DATA 

CLOCK 

LOAD 

+5V 

PL1 

HEADER 5X2 

+12V 

Local/Remote 

/LOCK 

LOCK 

FSK-ID-CHAN 

REMOTE FREQUENCY CONTROL 

9 

7 

5 

3 

1 

8 

6 

4 

2 

D1 

1N4148 

RP1 

100K RPACK 

4 

10 

U4B 

74HC14 

SW1 

10 

9 

8 

7 

6 

5 

4 

3 

2 

1 

9 

7 

5 

3 

1 

8 

6 

4 

2 

3 

26 

24 

22 

20 

18 

16 

14 

12 

10 

8 

6 

4 

2 

5 

4 

3 

2 

1 

U1 

74HC165 

SER 

A 

J1 

25 

23 

21 

19 

17 

15 

13 

11 

9 

7 

5 

3 

1 

SW2 

2 

RECEPT 13X2 

5 

4 

3 

2 

1 

U4A 

74HC14 

B 

C 

D 

E 

F 

FSK-R 

9 

QH 

G 

H 

SW3 

10 

11 

12 

13 

14 

3 

4 

5 

6 

7 

QH 

CLK 

INH 

SH/LD 

2 

15 

1 

-12V 

+12V 

GND 

GND 

5 

4 

3 

2 

1 

1 

C1 

33PF NPO 

U2 

74HC165 

SER 

A 

SW4 

5 

4 

3 

2 

1 

COMPOSITE IN 

Local/Remote 

FSK 

R5 

1.0K 

1% 

10.24MHZ 

Y1 

R4 100K 1% 

C2 

39PF NPO 

SW5 

G 

H 

B 

C 

D 

E 

F 

9 

QH 

10 

11 

12 

13 

14 

3 

4 

5 

6 

5 

4 

3 

2 

1 

7 

QH 

CLK 

INH 

SH/LD 

2 

15 

1 

10 

9 

8 

7 

6 

5 

4 

3 

2 

1 

C3 

1-10PF 

OSC in 

OSC out 

R2 

10.0K 

1% 

D2 

1N4148 

TP 

LOAD 

DATA 

CLK 

R1 

10.0K 

1% 

RP2 

100K RPACK 

C41 

100PF 

Frequency Select 

8 

9 

C35 

.001 

PB1 

RESET 

+5V 

1 

2 

3 

4 

5 

6 

7 

8 

9 

RA2 

RA3 

RTC 

CLR 

VSS 

RB0 

RB1 

RB2 

RB3 

1 

2 

3 

Fin 4 

5 

6 

7 

8 

U3 

PIC16C61 

R17 

1K BECKMAN 

D3 

1N4148 

C42 

.001 

CH. SEL. 

DIRECT FSK 

ID 

FSK 

C6 

100PF 

R19 

25K 

LF SEP. 

AUTO ID 

LOCK DET. 

+5V 

BAND LIMIT 

R45 

10K 

R24 

150 

R44 

10.0K 

1% 

R46 

39K 

+5V 

R43 

1.0K 

R47 

1.0K 

1% 1% 

9 8 5 6 

U4D 

74HC14 

FSK BAL. 

UNCONTROLLED 

2 

A2 

1 

MAR-6 

U4C 

74HC14 

UNLESS OTHERWISE MARKED IN RED INK BY CM AS A 

CONTROLLED COPY, COPIES OF THESE DOCUMENTS 

INCLUDING ASSOCIATED ELECTRONIC REPRODUCTIONS 


THESE DRAWINGS AND SPECIFICATIONS ARE THE 

PROPERTY OF INTERNATIONAL RADIO CORP. 

AND SHALL NOT BE REPRODUCED, COPIED OR USED AS 

THE BASIS FOR THE MANUFACTURE OR SALE OF APPARATUS OR 

DEVICES WITHOUT PERMISSION. 

1 2 3 4 5 6 7 8 9 10 11 12 

C31 

.001 

C32 

.001 

R48 

1.0K 

1% 

C7 

.001 

13 12 

U4F 

74HC14 

U6 

VDD 

R7 10 

16 

C11 .001 

1 16 

15 

2 15 

C4 

C13 

14 

3 14 

1 3900PF 

13 

9 

4 13 

12 

5 12 

R6 

8 

U5C 

11 

6 11 

100K 

10 

10 

7 10 

1% 

MC33284P 

R10 

9 

100K 

8 9 

1% 

MC145170 

R8 

100 

CLOCK 

1% 

/ENABLE 

D12 

DATA 

1N4148 

+5V 

6 

7 

VDD 

U5B 

5 

R13 

100K 

R3 

MC33284P 

1% 

150K 

18 

RA1 

17 

RA0 

16 

R14 

OSC1 

15 

100K 

OSC2 

C5 

14 

1% 

VDD 

13 

.001 POLY 

RB7 

12 

R21 

RB6 

11 

100K 

RB5 

10 

1% 

RB4 

D5 1N4148 

C28 1 

POLY 

R20 1M 

R18 

VU5 

68K 

C43 

2 

D4 

1 

1 

1N4148 

U5A 

3 

MC33284P 

C29 

R27 10.0K 1% 

R28 10.0K 1% 

R41 10.0K 1% 

R42 10.0K 1% 

R40 10.0K 1% 

D6 

1N4148 

1 2 

3 4 

5 6 

7 8 

9 10 

+ C30 

10/35V 

TANT. 

HD2 

HEADER 5X2 

4 

11 

DL3 

AMBER 

R9 

100K 

1% 

1 

R22 

200K 

C12 

1 

R23 

1M 

POLY 

C8 

1 

3 

R11 

100K 

1% 

C14 

.001 POLY 

D7 

1N4148 

+ C27 

10/35V 

TANT. 

11 10 

D9 

1N4148 

13 

12 

D10 

1N4148 

U4E 

74HC14 

MC33284P 

U5D 

+5V 

D8 

1N4148 

R15 

100K 

1% 

TP1 

14 

C33 

33pF 

C9 

.001 

C10 

.001 

/LOCK 

R12 

1.0K 

1% 

R16 

100K 

1% 

FSK-R 

LOCK 

C15 

0.01 

DL1 

GREEN 

DL2 

RED 

+5V 

R80 

24.3K 1% 

R90 

499 1% 

C76 

0.1 

R25 

680 

R26 

680 

+12V 

R88 

30.1K 1% 

DWN 

CHK 

CM 

PE 

K 

VU5 

C77 

0.1 

R82 

24.3K 1% 

FILENAME: 

3 

2 

3 

3 

R30 

10 

R61 

10.0K 

1% 

C62 

220pF 

R64 4.99K 

R65 

100K 

1% 

8 4 

+12V 

R85 

2K 

PWR. CNTRL. OFFSET 

IN 

IN 

VR3 

LM317 

C 

2 

C 

2 

R62 

100 

1% 

OUT 

VR2 

LM78L05 

OUT 

APPROVALS 

DISTRIBUTION 

1 

+12V 

8 

NE5532 

U7A 

4 

VVCO 

R63 

39 

1 

1 

R33 

100 

1% 

7 

5 

3 

1 

8 

6 

4 

2 

2 

37 

R51 

237 

1% 

R52 

1.27K 

1% 

+12V 

VCO61 

POS-150 

IREC 

INTERNATIONAL RADIO AND ELECTRONICS CORP. 

25166 LEER DRIVE ELKHART, IN. 46514 

574-262-8900 WWW.IREC1.COM 

TITLE: 

SIZE 

C 

R66 

150 

U7B 

NE5532 

C19 

.001 

-12V 

R81 

10.0K 

U8A 

1 

1% 

6 

TL072 5 

R89 

26.7K 1% 

+ C36 

10/35V 

TANT. 

1% 

C78 0.1 

R87 

10K 

PWR. CNTRL TILT 

R86 

-12V 

680.0 

C79 0.1 

D14 

6.2V 1N753A 

+ C37 

10/35V 

TANT. 

DW 01-04-02 

DJ 01-05-02 

DW 01-05-02 

DP 01-05-02 

+ C61 

47/20V 

TANT. 

R67 

15 

8.26V 

SCALE : NONE 

5 

6 

C81 

1000pF 

R68 

499K 

1% 

U8B 

TL072 

+ C39 

10/35V 

TANT. 

DWG . NO . 

R35 499K 

1% 

+ D11 

C21 1N4148 

10/35V 

TANT. 

7 

+ C38 

10/35V 

TANT. 

C40 

1 

+8V 

C23 

.001 

C24 

33pF NPO 

+5V 

C44 

1 

R84 

5.11K 1% 

200440-SCH 

PROJ NO. 

C22 

.001 

1 

+8V 

R83 

5.11K 1% 

G 

Q72 

IRFD9120 

TP2 

4.5 - 8.0V 

3 

NOTES : 

MAR-6 

A1 

S 

D 

+8V 

2 

R38 

15 

R39 

100 

1% 

C26 

.001 

1. ALL RESISTORS ARE IN OHMS, 

1/4W, 5% TOL. 

2. ALL CAPACITORS ARE IN MICROFARADS. 

509 

1 

D13 

3.9V 

SCH, FM-VFM RF EXCITER 

JP1 

JUMPER 

2 

C80 

0.1 

SHEET 

C82 

.01 

RF OUT 

UNLESS OTHERWISE SPECIFIED: 

REFERENCE DESIGNATORS NOT USED: 

C16, C17, C18, C20, C25, C34, C45-60, C63-75, 

Q1-71, R29, R31, R32, R34, R36, R37, R49, R50, 

R53-60, R69-79, VCO1-VCO60. 

OF 

REV 

A 

1 1 

G 

F 

E 

D 

C 

B 

A

D 8169-1 

Illustration 6-8 RF Metering Board 


PAV 

J2-4 

PAI 

J2-3 

TEMP OUT 

J2-6 

DC SUPPLY 

J2-2 

VOLTMETER 

J2-8 

RF REV 

J2-11 

RF FWD 

J2-10 

RFV 

J2-9 

R401 

1N4148 

R469 

10K 

R418 

1K 

C431 

0.1 

C418 

.01 

C412 

0.1 

C406 

.01 

C401 

.01 

U407A +12V 

TL074 

2 

4 

3 

11 

-12V 

R452 

10K 1 

R453 

1.1K 1 

(Jumper under board) 

C421 

.001 

R420 

100K 1 

9 

10 

R419 

24.9K 

SWR LIMIT= 

R451 

100K 1 

R457 

10K 

C414 

.01 

R461 

10K 

C416 

.01 

U406A 

TL074 

U7 

1 

C419 

.001 

Parts not loaded: 

2 

3 

C403, 404 

DZ401 

R402, 403, 404 

Q401, 402 

U401 

LB401 

U3 

8 

U403C 

TL074 

6 

5 

+12V 

-12V 

4 

11 

U406B 

TL074 

6 

5 

D415 

1N6263 

(R435+R436)+R436 

---------------- = ---- 

(R435+R436)-R436 

R470 

22K 

U6 

U3 

7 

U403B 

TL074 

1 

C415 

.001 

U6 

7 

C417 

.001 

R471 

100K 

R455 

100K 1 

50mv per degree C. 

D413 

1N6263 

D414 

1N6263 

R421 

100 

POWER CAL 

R472 

10K POT H 

R458 

22K 

R462 

22K 

R405 

2.49K 1 

R406 

100K 1 

5.00V = 100 deg. C 

10mV/Deg. C 

R454 

100 

R456 

1K 1 

R473 

10K 

150K 

100K 

R459 

100K 

R463 

100K 

6 

5 

-12V 

+12V +5.00V 

8 U2 

R409 

2 

100 

J4-3 

1 

REM PADCV 

R411 

3 

1.00V = 10VDC 

15K 

U402A 

4 TL072 

R412 

-12V 

10K POT H 

6 

5 

J4-6 

REM PATEMP 

= 1.5:1 

C420 

.01 

D416 

U7 

R407 

10.0K 1 

R408 

1.1K 1 

R422 

75k 

R423 

240K 

REM BATT 

J4-7 

7 

U407B 

TL074 

C413 

0.1 

R474 

3.3K 

7 

U402B 

TL072 

R410 

100 

R424 

100k 

-12V 

J4-4 

REM PADCA 

1.00V = 10.0A 

2 

3 

LM394 

1 

8 

C1 

8 C 

2 

7 

B2 

7 B 

3 

6 

E3 

6 E 

4 

5 

4 5 

Q405 

LM394 

1 

8 

2 

C1 

8 C 

7 

3 

B2 

7 B 

6 

E3 

6 E 

4 

5 

Q406 

4 5 

+12V 

-12V 

R475 

49.9K 

U3 

4 

1 

U403A 

11 TL074 

R426 

30.1K 1 

R427 

240K 

RF LEVEL 

J3-8 

R425 

1M 

POWER SET 

-6.9V 

C407 

.001 

R434 

10K POT H 

10mV/Volt 

100mV/Amp 

1mV/Degree C 

10mV/Volt 

10mV/Volt 

9 

10 

13 

12 

R428 

10K 

R435 

100K 

R460 

1K 

R476 

49.9K 

U7 

8 

U407C 

TL074 

R477 

7.5K 

U3 

R429 

220K 

14 

U403D 

TL074 

R436 

24.9K 

R440 

33K 

R413 

33K 

PAI LIMIT 

R478 

10.0K 1 

13 

12 

C408 

1.0UF 

U4 

14 

U404D 

TL074 

R430 

100K 

R414 

2.2M 

+12V R437 

1M 

2 

4 

U4 

1 

3 

U404A 

11 TL074 

9 

10 

-12V 

(2.5VDC at 100W) 

R479 

1.1K 1 

13 

12 

U4 

R441 

1M 

8 

U404C 

TL074 

.001V per Watt 

R464 

1K 

U7 

14 

U407D 

TL074 

C405 

.001 

C409 

.001 

C410 

0.1 

R415 

120K 

FAN 

J2-7 

D401 

D402 

R431 

120K 

(.135V) 

R480 

100 

D403 

R438 

120K 

R465 

56K 

D404 

R481 

39K 

R482 

1K 

+5V 

R416 

100K 

R432 

100K 

R439 

100K 

+5V 

RF POWER (RFV SQUARED) 

R466 

56K 

9 

10 

R483 

1M 

U6 

R484 

10K 

D417 

8 

U406C 

TL074 

R467 

1K POTH 

R468 

1K 

(Clamp SWR reading below 5W.) 

J4-5 

REM RFWATTS 

(1.00V at 100W) 

D418 

R442 

51K 

R485 

100K 

(VFWD+VREFL)/40 

SWR CAL 

Q403 

2N5210 

R486 

100K 

100K 

R487 

/LOCK 

J4-1 

INPUT 

J2-12 

+12V 

-12V 

D405 

C427 

1.0UF 

R443 

51K 

+5V 

13 

12 

C424 

1.0UF 

R492 

10K 

R489 

24.9K 

R444 

200K 

U5 

9 8 

U405D 

74HC14 

13 12 

U405F 

74HC14 

1 2 

U405A 

74HC14 

3 4 

U405B 

74HC14 

5 6 

U405C 

74HC14 

D412 

-12V 

C411 

0.1 

R488 

24.9K 

U6 

14 

U406D 

TL074 

+5.00V 

J3-9,10 

J4-12 

+12V 

C425 

1.0UF 

C428 

1.0UF 

1 

R445 

6 

5 

R446 

10K 

-12V 

100K 

U4 

7 

U404B 

TL074 

D406 

D407 

D408 

D409 

D410 

(VFWD-VREFL)/4 

VR401 

78L05 

IN OUT 

C 

2 

3 

+5.00V 

R450 

10K 

R447 

1K 

D411 

+5V 

11 10 

RF POWER 

SWR 

ALC 

PA DCV 

PA DCI 

PA TEMPERATURE 

SUPPLY DC VOLTS 

VOLTMETER 

+5.00V 

R491 

2.49K 1 

C426 

1.0UF 

VDD 

VCC 

+5V 

VSS 

VEE 

U405E 

74HC14 

R490 

10.0K 1 

SWR LAMP 

J3-20 

PADC LAMP 

J3-14 

FAULT SUM 

J4-8 

PATEMP LAMP 

J3-12 

R448 

100K 1 

R449 

11K 1 

J3-2 

J3-4 

J3-6 

LOCK LAMP 

J3-18 

/+28V INH 

J2-1 

INPUT LAMP 

J3-16 

C429 

1.0UF 

GND 

ALC 

J4-2 

FULL SCALE 

1999 WATTS 

19.99 

19.99V 

199.9V 

19.99A 

199.9 Deg. C 

199.9V 

199.9V 

1.00V 

SEL A 

SEL B 

SEL C 

-12V 

DZ402 

LM329DZ 

R417 

3.3K 

13 

14 

15 

12 

1 

5 

2 

4 

6 

11 

10 

9 

13 

14 

15 

12 

1 

5 

2 

4 

6 

11 

10 

9 

U8,9 pin 7 

10 9 

8 7 

-12V -12V 

6 5 

+12V 

+12V 

4 3 

2 1 

X0 

X1 

X2 

X3 

X4 

X5 

X6 

X7 

INH 

A 

B 

C 

X0 

X1 

X2 

X3 

X4 

X5 

X6 

X7 

INH 

A 

B 

C 

SEL A 

SEL B 

SEL C 

RF LEVEL 

+5.00V 

PATEMP LAMP 

PADC LAMP 

INPUT LAMP 

LOCK LAMP 

SWR LAMP 

+5V 

+5V 

16 

X 

8 

16 

X 

8 

-6.9V 

+5.00V 

3 

(1.999V reads "1999") 

U8 

U408 

74HC4051 

3 

U9 

U409 

74HC4051 

J401 

RECEPT 5X2 

INPUT 

RF REV 

RF FWD 

RFV 

VOLTMETER 

FAN 

TEMP OUT 

PAV 

PAI 

DC SUPPLY 

/+28V INH 

2 

4 

6 

8 

10 

12 

14 

16 

18 

20 

FAULT SUM 

REM BATT 

REM PATEMP 

REM RFWATTS 

REM PADCA 

REM PADCV 

ALC 

/LOCK 

C422 

0.1 

NUMBERS USED: 

R1-91 

C1-29 (C2) 

C423 

0.1 

HD403 

1 

3 

5 

7 

9 

11 

13 

15 

17 

19 

HEADER 10X2 

J402 

12 

11 

10 

9 

8 

7 

6 

5 

4 

3 

2 

1 

RECEPT 12X1 

+5.00V 

DPM REF 

DPM IN 

J404 

12 

11 

10 

9 

8 

7 

6 

5 

4 

3 

2 

1 

RECEPT 12X1 

DPM IN 

J3-19 

DPM REF 

J3-17 

FM500 

METERING 

103204A 

J2 

J3 

J4 

Metering 


6–11

1 

2 

3 

4 

5 

6 

7 

8 

9 

1 

2 

3 

4 

5 

6 

7 

8 

9 

1 

2 

3 

4 

5 

6 

7 

8 

9 

1 

2 

3 

4 

5 

6 

7 

8 

9 

1 

2 

3 

4 

5 

6 

7 

8 

9 

1 

2 

3 

4 

5 

6 

7 

8 

9 

3 

2 

1 

1 

2 

3 

4 

5 

6 

7 

8 

9 

1 

2 

3 

4 

5 

6 

7 

8 

9 

1 2 3 4 5 6 7 8 9 10 11 12 

1 

2 

1 

2 

3 

4 

1 

2 

3 

DWG. NO. 

4 201207-SCH 

REV. 

1 

5 

6 

7 

8 

9 

5 

10 

6 

11 

12 

H 

G 

FAN- 

+12V 

HD7 

HD2 

TP1 

VOLTMETER 

1 

2 

HEADER 2 .156 

1 

2 

3 

4 

5 

6 

HEADER 6X1 .156 

HD4 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

FAN 

R26 

1K 

+12V 

C10 

.01 

C25 C26 

.01 .01 

R29 1K 

R28 1K 

R27 1K 

C27 

.01 

Q1 

IRF541 

R25 

OPEN 

J4 

HD44 HEADER 12 

/LOCK 

ALC 

METER PAV 

METER PAI 

METER RFW 

METER PATEMP 

METER BATT 

FAULT SUM 

10 

11 

12 

10 

11 

12 

+5.00V 

ALC / METERING 

J2 

HD42 HEADER 12 

10 

11 

12 

10 

11 

12 

/LOCK FAULT 

DC SUPPLY 

PAI 

PAV 

TEMP 

FAN 

V-METER 

RFV 

RF FWD 

RF REV 

INPUT 

/LOCK 

ALC 

J1 

HD41 HEADER 5 x 2 

10 

10 

+12V 

-12V 

Z31 

OPEN 

ADD FOR M2HD-S 

MOTHERBOARD ONLY 

HD31 26 HEADER 

J1 

FSK IN 

NC 

/LOCK 

NC 

ALC 

RF EXCITER 

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20 

21 

22 

23 

24 

25 

26 

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20 

21 

22 

23 

24 

25 

26 

+12V 

-12V 

RFX OUT 

J5 

MCX 

J6 

MCX 

C54 

1.0 

+12V 

AUDIO PROCESSOR SHUNT 

U2 

C50 

+12V 

1 

8 

NC NC 

1.0 

2 

7 

2 TL072 

Vin NC 

1 

U3A 

3 

6 

3 

TEMP Vout 

C51 

4 

5 

GND TRM 

-12V 

1.0 

REF02 

6 TL072 

7 

U3B 

5 

C52 

.01 

R42 

4.7K 

R43 

100 

C54 

1.0 


APPROVALS 


DATE DWN CHK CM 

1 02-05-05 DW DW 

FOR PROTOTYPE 

+5.00V 

Z9 

OPEN 

AUDIO PROCESSOR 

PE 

H 

G 

HEADER 5 x 2 

F 

E 

D 

V+ 

TEMP 

GND 

HD5 

1 

2 

3 

HEADER 3X1 

HD3 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20 

HEADER 10 x 2 

C40 

OPEN 

C39 

OPEN 

C38 

OPEN 

C36 

.01 

C35 

.01 

C34 

.01 

C33 

.01 

C32 

.01 

C30 

.01 

C31 

.01 

C29 

.001 

C28 

.001 

+12V 

NC 

NC 

NC 

NC 

NC 

NC 

INPUT 

TEMP 

C41 

.001 

C42 

.001 

C43 

.001 

ALC 

ALC 

METER PAV 

Z15 OPEN 

Z16 OPEN 

METER PAI 

Z17 OPEN 

METER RFW 

Z18 OPEN 

METER PATEMP 

Z19 OPEN 

METER BATT 

Z20 OPEN 

FAULT SUM 

Z21 OPEN 

Z22 OPEN 

Z30 

JUMPER 

Z29 

JUMPER 

Z28 

JUMPER 

Z27 

JUMPER 

Z26 

JUMPER 

Z25 

JUMPER 

Z24 

JUMPER 

Z23 

JUMPER 

C17 

.01 

C18 

.01 

C19 

.01 

C20 

.01 

C21 

.01 

C22 

.01 

C23 

.01 

C24 

.01 

FSK IN 

COMP METER 

38KHZ 

COMP METER 

/EXT ENABLE 

COMP OUT 

COMP OUT 

COMP METER 

/EXT ENABLE 

LEFT 

RIGHT 

MON L 

MON R 

LPIN L 

LPOUT L 

LPIN R 

LPOUT R 

38KHZ 

LEFT 

RIGHT 

L IN1 

L IN2 

R IN1 

R IN2 

LPIN L 

LPOUT L 

LPIN R 

LPOUT R 

+5.00V 

STEREO/MON 

NC 

NC 

NC 

NC 

NC 

HD12 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

HEADER 5 x 2 

HD11 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20 

HEADER 10 x 2 

HD22 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

HEADER 12 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20 

J2 

J1 

STEREO GENERATOR 

HD13 

1 

2 

3 

4 

5 

6 

7 J2 

8 

9 

10 

HD23 

11 

12 1 

1 

2 

2 

3 

3 

4 

4 

5 

5 

J3 6 

6 

7 

7 

8 

8 

9 

9 

10 10 

J3 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20 

21 

22 

23 

24 

25 

26 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20 

21 

22 

23 

24 

25 

26 

HEADER 13 x 2 

HEADER 5 x 2 

NC 

+12V 

+12V 

-12V 

/+6DB 

/+12DB 

L VU 

R VU 

+5.00V 

PROC A 

PROC B 

PROC C 

BR GR 

HI GR 

COMP METER 

STEREO/MON 

Z32 

Z33 

+5.00V 

OPEN OPEN 

INSTALLED WHEN USING 

AUDIO PROC. SHUNT CKT. 

+12V 

-12V 

+12V 

+12V 

+5.00V 

HD61 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20 

HEADER 10 x 2 

TP2 

+12V 

TP3 

-12V 

TP4 

+12V 

TP5 

GND 

F 

E 

D 

C 

B 

A 

J4 

DB15 

8 

15 

7 

14 

6 

13 

5 

12 

4 

11 

3 

10 

2 

9 

1 

_METER PAV 

_METER PAI 

_METER RFW 

_METER PA TEMP 

_METER BATT 

_FAULT SUM 

_/AUTO CAR. OFF 

_/CARRIER OFF 

_FSK IN 

_ALC 

_COMPOSITE OUT 

_38 KHZ OUT 

_/EXT ENABLE 

R16 220 

R15 100 

R14 390 

R13 390 

R12 1K 

R11 220 

JMP1 OPEN 

ALC 

D1 

1N4148 

C11 

.01 

C12 

R24 220 

OPEN 

C13 

R23 220 

.001 

R22 220 

C14 

.001 

R21 220 

C15 

.01 

R20 220 

C16 

R19 220 

.01 

R18 220 

R17 220 

JMP2 OPEN 

FSK IN 

COMP METER 

/EXT ENABLE 

J1 

XLR 

Z5 

OPEN 

Z3 

OPEN 

Z6 

Z4 

R1 

1K 

R2 

1K 

Z1 

JUMPER 

INPUT CONFIGURATION CHART 

NON-OMNIA BOARD INPUT IMPEDENCE 

50 KOHM 

Z1, Z2 ON 

Z3, Z5, Z7, Z8 OFF 

Z4, Z6 OFF 

600 OHM 

Z1, Z2 ON 

Z3, Z5, Z7, Z8 ON 

Z4, Z6 OFF 

R1A 

300 

R2A 

300 

OPEN 

OPEN 

C2 

220pF 

OMNIA BOARD AES/EBU INPUT 

Z1, Z2 OFF 

Z3, Z5, Z7, Z8 OFF 

Z4, Z6 ON 

ANALOG LEFT/RIGHT 

LEFT IN 1 LEFT IN 2 

L IN1 

R IN1 

Z2 

JUMPER 

C1 

220pF 

R IN1 

L IN2 

HI 

2 

LO 

3 

GND 

1 

REF. FOR 

XLR CON. 

L IN2 

R IN2 

C3 

220pF 

R4 

1K 

C4 

220pF 

R3A 

300 

R4A 

300 

R3 

1K 

Z7 

OPEN 

Z8 

OPEN 

3J2 

OPEN 

R9 

1K 

5HD6 

OPEN 

R8 

1K 

EXT IN 

R5 

1K 

MON_R 

MON_L 

EXT_IN 

EXT_RTN 

SCA 

EXT RTN 

R6 

1K 

SCA IN 

C9 

220pF 

C8 

220pF 

C5 

220pF 

C6 

220pF 

C7 

220pF 

R7 

1K 

R10 

240 

COMP OUT 

SCA IN 

EXT RTN 

EXT IN 

COMP METER 

Z13 

OPEN 

Z12 

OPEN 

Z14 

OPEN 

Z11 

OPEN 

Z10 

OPEN 

HD21 

UNCONTROLLED 





1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

HEADER 12 

R33 

24.9K 

1% 

R35 

24.9K 

1% 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

2 

3 

J1 

STEREO GENERATOR SHUNT 

+12V 

-12V 

R36 

24.9K 

1% 

R41 1K 

R34 24.9K 1% 

C48 

1.0 

TL072 

1 

U1A 

C49 

1.0 

D2 

1N4148 

R37 

1N4148 

D3 

3.9K 5 


PROPERTY OF INTERNATIONAL RADIO AND ELECTRONICS CORP. 




6 

R32 

1K 

R40 

100 

R39 

100 

R38 

4.02K 

1% 

TL072 

7 

U1B 

DWN 

CHK 

CM 

PE 

K 

FILENAME: 

APPROVALS 

DISTRIBUTION 

-12V 

DW 11-23-04 

DW 11-23-04 

IREC 



Error 574-262-8900 : logo3A.jpg file not found. WWW.IREC1.COM 

TITLE: 

SCH, FM/IBOC MOTHER BOARD 

SIZE 

D 

DWG . NO . 

SCALE : NONE 

NOTES: 


1. ALL RESISTORS ARE IN OHMS, 1/4W, 5% TOL. 


201207-SCH 

PROJ NO. 

SHEET 

REV 

1 

1 OF 1 

C 

B 

A

Jumper FMA "E" FMA "T" FMA"T" FMA "R" FMA "Omnia" FMA "Omnia" FMX "E" FMX "T" FMX "T" FMX "R" FMX "Omnia" FMX "Omnia" FMX 

50K input 600 input Analog input AES input 50K input 600 input Analog input AES input RMS 

Z1 Short Short Short Short Short Open Short Short Short Short Short Open 

Z2 Short Short Short Short Short Open Short Short Short Short Short Open 

Z3 Open Open Short Open Open Open Open Open Short Open Open Open 

Z4 Open Open Open Open Open Short Open Open Open Open Open Short 


Z6 Open Open Open Open Open Short Open Open Open Open Open Short 



Z9 Short Open Open Open Open Open Short Open Open Open Open Open 






Z15 Open Open Open Open Open Open Open Open Open Open Open Open Short 





Z20 Open Open Open Open Open Open Open Open Open Open Open Open Open 



Z23 Short Short Short Short Short Short Short Short Short Short Short Short Open 





Z28 Short Short Short Short Short Short Short Short Short Short Short Short Short 



Z31 Open Open Open Open Open Open Open Open Open Open Open Open 



JMP1 Open Open Open Open Open Open Open Open Open Open Open Open Open 

JMP2 Open Open Open Open Open Open Open Open Open Open Open Open Open

R27 

D 8167-5 

Illustration 6-10 Display Board 

Reference Drawings 6 - 15

L VU 

C601 

1.0UF 

C603 

1.0UF 

R VU 

DL101 

DISPLAY 

DPM IN 

DPM REF 

+5V 

R601 

68K 

R607 

68K 

R635 

100K 

R636 

100K 

2 

3 

6 

5 

+12V 

-12V 

8 

4 

1 

U601A 

TL072 

7 

U601B 

TL072 

+5V 

R602 

100K 

D601 

1N4148 

D602 

1N4148 

R608 

100K 

D603 

1N4148 

D604 

1N4148 

R603 

1K 

R609 

1K 

+12V 

R604 

1.2K 

C602 

1.0UF 

+12V 

R610 

1.2K 

C604 

1.0UF 

JP601 

5.00V 

+12V 

5.00V 

+12V 

JP602 

2 1 1 1 1 1 1 1 1 1 1 

0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 

1000 

100's 

TENS 

UNITS 

2 

1 2 2 2 3 2 4 2 5 2 6 2 7 2 8 2 9 3 0 3 1 3 2 3 3 3 4 3 5 3 6 3 7 3 8 3 9 4 0 

C614 

0.1 

C615 

0.1 

2 1 1 1 1 1 1 1 1 1 1 

0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 

2 

1 2 2 2 3 2 4 2 5 2 6 2 7 2 8 2 9 3 0 3 1 3 2 3 3 3 4 3 5 3 6 3 7 3 8 3 9 4 0 

C616 

0.1 POLY 

U612 

R637 

470K 

ICL7107 

C617 

0.1 

C618 

0.1 

C619 

100PF 

9 

8 

7 

6 

5 

4 

3 

2 

1 

9 

8 

7 

6 

5 

4 

3 

2 

1 

R638 

100K 

+5V 

MODE 

RADJ 

ROUT 

DHI 

IN 

DLO 

V+ 

V- 

L1 

U602 

LM3915 

MODE 

RADJ 

ROUT 

DHI 

IN 

DLO 

V+ 

V- 

L1 

U603 

LM3915 

C627 

1.0UF 

L10 

L9 

L8 

L7 

L6 

L5 

L4 

L3 

L2 

R605 

1K 

L10 

L9 

L8 

L7 

L6 

L5 

L4 

L3 

L2 

R611 

1K 

10 

11 

12 

13 

14 

15 

16 

17 

18 

10 

11 

12 

13 

14 

15 

16 

17 

18 

DP10 

DP100 

DZ601 

6.2V 

DL601-610 

DL11-20 

R651 

2.2K 

RED 

RED 

Q601 

MPS-A56 

RED 

YEL 

GRN 

GRN 

GRN 

GRN 

50mA 

GRN 

+5V 

GRN 

GRN 

R606 

330 

RED 

YEL 

GRN 

GRN 

GRN 

GRN 

50mA 

GRN 

+5V 

GRN 

GRN 

R612 

Q602 

MPS-A56 

-12V 

330 

+12V 

-12V 

C623 

1.0UF 

2 

3 

HI GR 

DITHER 

BR GR 

+12V 

-12V 

1 

C622 

1.0UF 

U609C 

74HC14 

5 6 

8 

U609D 

74HC14 

9 8 

U609E 

74HC14 

11 10 

R613 

1K 

R617 

1K 

1 

4 U606A 

TL072 

VR601 

7805 

IN OUT 

C 

2 

C606 

0.1 

R615 

33K 

R616 

33K 

R631 

5.6K 

3 

R632 

620 

-12V 

C630 

1.0UF 

C607 

0.1 

C608 

.001 

C631 

1.0UF 

G 

C624 

1.0UF 

+5V 

1 

8 

L 

2 

L 

1 

1 

L 

2 

+5V 

G G G Y 

C605 

.001 

1 

8 

L 

1 

1 

1 

7 

L 

3 

U604 

V 

- 

2 

L 

3 

V 

- 

L 

4 

+12V 

1 

7 

U605 

2 

1 

6 

V 

+ 

+12V 

3 

1 

6 

L 

4 

V 

+ 

3 

1 

5 

L 

5 

D 

L 

O 

4 

1 

4 

L 

6 

LM3914 

+5V 

1 

5 

L 

5 

D 

L 

O 

4 

I 

N 

DL621-625 

5 

L 

6 

LM3914 

L 

7 

5.00V 

1 

4 

I 

N 

5 

1 

3 

D 

H 

I 

5.00V 

6 

1 

3 

L 

7 

D 

H 

I 

6 

1 

2 

L 

8 

R 

O 

U 

T 

7 

1 

2 

L 

8 

R 

O 

U 

T 

7 

1 

1 

L 

9 

R 

A 

D 

J 

8 

R614 

1.2K 

Y Y G G G G G G Y 

D616 

UP 

SW605 

DOWN 

SW606 

+12V 

C629 

1.0UF 

D617 

R633 

33K 

R634 

5.1K 

R639 

100K 

R640 

100K 

U9 

R628 

1K 

R654 

1K 

14 

7 

6 

5 

1 

1 

L 

9 

R 

A 

D 

J 

8 

R618 

1.2K 

C613 

.01 

1 

0 

L 

1 

0 

M 

O 

D 

E 

9 

1 

0 

L 

1 

0 

M 

O 

D 

E 

RED 

9 

U606B 

TL072 

C620 

.01 

C621 

.01 

7 

16 

U10 

U11 

8 

C632 

.001 

C633 

.001 

DL626-635 

DITHER 

10V P-P DITHER 

VDD 

VCC 

+5V 

VEE 

VSS 

R641 

10K 

R642 

10K 

+12V 

C626 

1.0UF 

R645 

100 

R644 

33K 

Q604 

2N5087 

D605 

COMPOSITE -12V 

R622 

10.0K 

U607A 

TL072 

U609A 

74HC14 

1 2 

U609B 

74HC14 

3 4 

2 

3 

PROC A 

PROC B 

PROC C 

R623 

10.0K 

+12V 

-12V 

8 

4 

1 

RF POWER 

SWR 

ALC 

PA DC VOLTS 

PA DC AMPS 

SUPPLY DC VOLTS 

1N6263 

D606 

1N6263 

R624 

1M 

DECIMAL POINT 

DP100 

PA TEMPERATURE 

VOLTMETER 

+5V 

DP10 

F.S. 

1999 

19.99 

19.99 

199.9 

19.99 

199.9 

199.9 

199.9 

R653 

1K 

C612 

.001 

R650 

100K 

BECKMAN 

15 

1 

10 

9 

5 

4 

11 

14 

MOD. CAL. 

U610 

74HC193 

A 

B 

C 

D 

6 

5 

R655 

4.7K 

+5V 

U607B 

TL072 

7 

R649 

10K POT H 

D607 

SWR LAMP 

Q603 

2N5210 

R625 

10K 

LOCK LAMP 

INPUT 

PADC LAMP 

PATEMP LAMP 

R656 

220 DL636-643 

QA 

QB 

QC 

QD 

UP CO 

DN BO 

LOAD 

CLR 

3 

2 

6 

7 

12 

13 

GRN 

GRN 

GRN 

GRN 

GRN 

GRN 

GRN 

GRN 

R646 

10M 

C610 

0.1 

C611 

0.1 

R643 

3.3M 

SWR 

D618 

DL644-647, 659 

DL644 

RED 

LOCK 

DL645 

RED 

INPUT 

DL646 

RED 

PA DC 

DL647 

RED 

PA TEMP 

DL659 

RED 

6 

5 

+12V 

2 

3 

U613A 

TL072 

-12V 

8 

4 

DITHER 

R619 

510 

U613B 

TL072 

7 

12 

1 

R620 

220K 

U611 

74HC4051 

13 

3 

X0 X 

14 

X1 

15 

X2 

12 

X3 

1 

X4 

5 

X5 

2 

X6 

4 

X7 

6 

INH 

11 

A 

10 

B 

9 

C 

NOTES : 

SEL A 

SEL B 

SEL C 

5.00V 

R647 

1K 

C625 

0.1 

C634 

1.0UF 

U609F 

74HC14 

R630 

150 

C609 

1.0UF 

13 

JP603 

JUMPER 

FOR BAR 

R626 

33K 

R627 

2.7K 

R648 

1K 

5.00V 

+12V 

+12V 

U608 

LM3914 

9 

MODE L10 

8 

RADJ L9 

7 

ROUT L8 

6 

DHI L7 

5 

IN 

L6 

4 

DLO L5 

3 

V+ L4 

2 

V- 

L3 

1 

L1 L2 

+5V 

R657 

1K BECKMAN 


2. ALL CAPACITORS ARE IN MICROFARADS UNLESS OTHERWISE SPECIFIED. 

SW603 

10 

11 

12 

13 

14 

15 

16 

17 

18 

SW601 

SW602 

DL648-658 

R652 

5.6K 

STEREO 

MONO 

"110" 

"PILOT" 

Pin 1, upper left from front of unit. 

+5V 

RED 

YEL 

GRN 

GRN 

GRN 

GRN 

GRN 

GRN 

GRN 

GRN 

GRN 

R629 

680 

ST/MON 

RF LEVEL 

/+6DB 

/+12DB 

J601 

+12V +12V 

2 1 

-12V 

-12V 

4 3 

L VU 

/+12DB 

6 5 

R VU 

/+6DB 

8 7 

5.00V 

5.00V 

10 9 

PROC A 

12 11 

PROC B 

14 13 

PROC C 

COMPOSITE 

16 15 

BR GR 

18 17 

HI GR 

MON/ST 

20 19 

GND 

HEADER 10X2 

J602 

SEL A 

2 1 

SEL B 

4 3 

SEL C 

6 5 

RF LEVEL 

8 7 

5.00V 5.00V 

10 9 

PATEMP LAMP 

12 11 

PADC LAMP 

14 13 

INPUT 

16 15 

LOCK LAMP 

DPM REF 

18 17 

SWR LAMP 

DPM IN 

20 19 

HEADER 10X2 

C628 

1.0UF 

+12V 

-12V 

SCM, FM DISPLAY 

103206 

Display 

6 - 16

2 

4 

6 

8 

3 

2 

1 

1 

3 

5 

7 

9 

6 

5 

4 

3 

2 

1 

1 

8 

1 2 3 4 5 6 DWG. NO. 

REV. 

8 9 10 11 12 

Q43229-6 

AC 

H 

H 

CARR SW 

/CARRIER OFF 

R1 

4.7K 

R2 

10.0K 

U3C 

5 6 

R33 

4.7K 

74HC14 

G 

F 

E 

D 

C 

B 

A 


/AUTO CARRIER 

AUDIO or COMPOSITE 

COMP2 

C7 

.001 

CARR SW 

DRVR V+ 

VDD 

C1 

.01 

COMP2 

38KHZ 

/CARRIER OFF 

/AUTO CARRIER 

R25 

100K 

VDD 

C2 

.001 

R3 

4.7K 

R4 

10.0K 

R7 

120K 

C3 

-12V 

.001 

2 U1A 

1 

3 

R6 

TL074 

5.1K 

R5 

91K 

R10 

75K 

13 12 

R26 

100K 

HD1 

U3F 

74HC14 

+12V 

-12V 

1% 

D15 

1N4004 

C4 

.001 

C8 

220pF 

VDD 

/LOCK FAULT 

13 

12 

U3A 

1 2 

4 11 

74HC14 

U1D 

R48 

10.0K U3E 

+12V 

TL074 

11 10 

HD2 

HEADER 10X2 

74HC14 

C26 0.1 

C27 

0.1 

FM 30/100/250 = C 8667-5 

14 

11 

13 

15 

17 

19 

10 

12 

14 

16 

18 

20 

D3 

1N6263 

D4 

1N6263 

R49 

1.5K 

U3B 

3 4 

PROGRAM DETECT 

METER UNREG 

D9 

OPEN 

R50 

100 

74HC14 

R27 

620.0 

R8 

51K 

+UNREG 

R11 

100K 

INPUT FAULT 

+12V 

R51 

(JUMPER) 

C9 

2200Pf 

POLY 

HD3 

FAN 

D2 

1N4148 

R12 

1.0M 

FM 30/100/250 = C 7746-8 

D1 

1N4148 

R9 

1.0K 

C5 

1.0 

POLY 

C10 

56Pf 

NPO 

+12V 

R13 

100K 

C11 

.01 

R28 

68K 

6 

5 

R14 

220.0 

R29 

4.12K 

1% 

FM 30/100/250 = D 6977-9 

HD4 

SYNC 

-12V 

6 

DRVR V+ 

5 

PAV 

4 

PAI 

3 

ALC 

2 

1 

HEADER 6 

(TO POWER REG. BOARD) 

U1B 

TL074 

DL1 

GREEN 

1 

2 

3 

4 

7 

-IN 

+IN 

D6 

1N4148 

R15 

2.2K 

U4 

LM3578 

OSC 

GND 

R32 

SEE NOTE 3 

-12V 

+12V 

3 

-12V 

C22 

3300/16V 

+12V 

+ 

V+ 

CS 

C 

E 

Vout 

DL2 

RED 

GND 

8 

7 

6 

5 

L4 

960 uH 

R16 

10.0K 

Vin 

+ 

R17 

10.0K 

R30 

2.2K C13 

100Pf 

2 

C21 

220/63V 

C12 

1.0 

D14 

1N5822 

UNCONTROLLED 










TITLE: 

SCH, FM/30/100/250 VOLTAGE REGULATOR 

1 2 3 4 5 6 7 8 9 10 11 12 

12 

11 

R18 

100K 

C16 

C20 

1800/35V 

1 

2 

3 

4 

C24 

10/35V 

L3 

960UH 

+ 

+ 

8 

RST 

CIN 

VCC 

IN 

ERR 

ESS 

VDD 

U2 

74HC4060 

16 

VCC 

GND 

U1C 

TL074 

U5 

IR2125 

VB 

OUT 

CS 

VS 

Q4 

Q5 

Q6 

Q7 

Q8 

Q9 

Q10 

Q12 

Q13 

Q14 

COUT 

COUT 

D13 

1N5822 

9 

10 

DZ4 

ICTE-12 

8 

7 

6 

5 

7 

5 

4 

6 

14 

13 

15 

1 

2 

3 

9 

10 

VDD 

Q5 

MPSA06 

R19 

10.0K 

D10 

1N4148 

R20 

10.0K 

L2 

960UH 

D7 

1N4148 

R21 

24.9K 

1% 

C14 

.1 

R24 

100.0 

C15 

0.1 

R45 

10.K 

1% 

C6 

1.0 

POLY 

DZ2 

1N966B 

R35 

51.0 

TIME-OUT SELECT 

JP1 

R34 

10.0K 

JP2 

OPEN 

VR1 OPEN 1 

.5 

2 

4 

8 

R37 

2 

4 

6 

8 

10 

1 

3 

5 

7 

9 

HEADER 5X2 

+UNREG 

Q1 

IRF540 

+ C23 

330/100V 

2.2K R38 R38A 

R36 1.0 1.0 

2.0K 0.5W 0.5W 

R44 

1.1K 

1% 

2 

OPEN 

2 

4 

OUT 

D11 

MUR120 

U6 

FEEDBACK 

Vin 

ON/OFF 

GND 

LM2576-ADJ 

1 

5 

3 

D8 

1N4148 

INPUT FAULT 

P1 

R22 

100K 

L1 

380UH 

U3D 

+12V 

9 8 

74HC14 

R23 

1.0K 

+6V 

DZ1 

1N4735 

6.2V 

VDD 

VCC 

VSS 

NOTES: 


1. ALL RESISTORS ARE IN OHMS, 1/4W, 5% TOL. 


3. FOR FM30, FM100, FM250 and FM500 UNITS, 

R32 VALUE = 82.5K OHM, 1/4W, 1% TOLERANCE 

FOR HARRIS UNITS, R32 VALUE = 100K OHM, 1/4W, 1% TOLERANCE 

+ C18 

220/63V 

DZ3 1.5KE36A 

R39 510 

SIZE 

C 

R40 

10.0 

+ C19 

1000/35V 

DWG . NO . 

SCALE : NONE 

Q3 

MPSA56 

R41 

1.0K 

PROJ NO. 

Q4 

MJE15028 

Q2 

MPSA06 

R42 

1.0K 

C28 

1 

R43 

220.0 

Q43229-6 

001,002,003 

SHEET 

DRVR V+ 

+ C25 

220/63V 

MANUFACTURED FOR HARRIS CORPORATION 

REV 

AC 

11 OF 11 

G 

F 

E 

D 

C 

B 

A

F 

1 2 3 4 5 

6 

7 8 

~ 

- + 

~ 

ON CHASSIS 

C1001 

0.015F 

110V 

BATTERY 

DC INPUT 

P801 

FASTON TAB 

P802 

FASTON TAB 

P806 

FASTON TAB 

1 

2 

3 

D804 

BYV72EW-150 



274 

DATE 

DWN 

A PRODUCTION RELEASE 10-31-03 DW 

APPROVALS 

CHK CM 

B CORRECTED Z3 AND Z6 UNIT STATUS FOR M2 AND FM100 01-29-04 DW DW DP 

323 C SWAPPED Z1, Z2 TO MATCH PWB 08-10-04 DW DW DP 

DW 

DP 

PE 

F 

P803 

FASTON TAB 

E 

D 

C 

B 

A 

B_L_SHT1_A.DOT REV. A 

1 

R802 

10K 

PA VOLTAGE SET 

PWB_REV.G 

3 

C10582-2 PWB_100969-1 

R801A 

27.4K 

R801B 

24.9K 

2 

2 

* 

* 

C801 

220PF C802 

2 

CIRCUIT BREAKER 

Z2 

Z1 

2200PF POLY 

1 

1 

C803 

56PF 

Z3 

1 2 

* 

* 

DZ806 

1N4735 6.2V 

C804 

.01 

R803 

82K 

1 2 

* 

Z7 

1 2 

* 

Z6 

1 2 

* 

Z9 

1 2 

* 

Z8 

R804 

10.0K 1% 

1 

2 

3 

4 

P804 + UNREG IN 

FASTON TAB 

P805 

FASTON TAB 

P807 

FASTON TAB 

-IN 

* 

+IN 

OSC 

GND 

R806A 

330K 

R806B 

200K 

R805A 

330K 

R805B 

200K 

R827 

1.0K 

U801 

LM3578AN 

V+ 

CS 

C 

E 

D805 

1N4148 

8 

7 

6 

5 

C814 

1/50V 

C815 

330/100V 

DZ801 

R807 

2.2K 

1N966B 16V 

C806 

4.7UF/63V 

R820 

100K 

L801 

ESS 

UNCONTROLLED 





+ 

+ 

C805 

100PF 

30UH 

C816 

+ 

330/100V 

1 

2 

3 

4 

C812 

1/50V 

VCC 

IN 

ERR 

U2 

IR2125 

VB 

OUT 

CS 

VS 

8 

7 

6 

5 

DZ807 

1N966B 16V 

UNIT CONFIGURATION 

+ C817 

330/100V 

JUMPER FM1 FM30 FM100 FM250 FM500 EURO HARRIS M1 

Z1 OPEN OPEN OPEN OPEN SHORT OPEN OPEN 

Z2 SHORT SHORT SHORT SHORT OPEN SHORT SHORT 

Z3 SHORT SHORT SHORT SHORT SHORT SHORT OPEN 

Z8 SHORT SHORT OPEN OPEN OPEN OPEN OPEN 

Z7 OPEN OPEN SHORT SHORT SHORT SHORT SHORT 

Z6 SHORT SHORT OPEN OPEN OPEN OPEN OPEN 

Z4 SHORT SHORT SHORT SHORT OPEN SHORT SHORT 

Z5 OPEN OPEN OPEN OPEN SHORT OPEN OPEN 

REF DES 

Z9 OPEN OPEN SHORT SHORT SHORT SHORT SHORT 

L802 

H43608-1 H43395-5 H43533-1 H43533-1 H43533-1 H43533-1 H43533-1 

R811 3.3K 3.3K 3.3K 3.3K 3.3K 5.11K 1% 3.3K 

R827 

OPEN OPEN OPEN OPEN OPEN OPEN INSTALLED 

R828 


DZ806 


DZ807 


* 

* 

D802 

1N4148 

C809 

.1 

C808 

.0027 

* 

3 

R808 

1.0K 

R828 

30K 

R809 

51.0 

2 

THESE DRAWINGS AND SPECIFICATIONS ARE THE PROPERTY OF 


AND ARE NOT TO BE REPRODUCED, COPIED OR USED AS THE BASIS 

FOR THE MANUFACTURE OR SALE OF APPARATUS OR 


SCALE : NONE 

1 2 3 4 5 

6 7 8 

R810 

2.0K 

1 

HARRIS M2 

SHORT 

OPEN 

OPEN 

SHORT 

OPEN 

OPEN 

SHORT 

SHORT 

H43533-1 

3.3K 

INSTALLED 

INSTALLED 

INSTALLED 

INSTALLED 

R811 

* 

R812A 

0.1 

5W 

D803 

BYV72EW-150 

Q801 

IRF540 

R812B 

0.1 

5W 

L802 

* 

NOTES: 

L803 

30UH 

+ C811 

C810 

330/100V 

UNLESS OTHERWISE 

SPECIFIED: 


1/4W, 5% TOL. 

2. ALL CAPACITORS ARE IN 

MICROFARADS. 

+ 

DWN 

CHK 

CM 

PE 

FILENAME: 

330/100V 

R818A 

2.0K 

2W 

APPROVALS 

R821 

10.0K 

DW 09-30-03 

DISTRIBUTION 

DZ803 

1N4735 6.2V 

R818B 

2.0K 

2W 

OPEN 

R814 

22.0K 

DW 09-30-03 

DP 09-30-03 

200915-SCH 

C813 

.01UF 

2 

3 

DZ802 

1N966B 16V 

TITLE: 

SIZE 

B 

7 

Q804 

MPSA06 

R815 

100.0 

U803 

OP-27GNB 

6 

4 

1 

8 

R819 

.04 OHM 15W 3% 

R813 

1.0K 

Q802 

MPSA56 

IREC 




SCH, FM POWER REGULATOR 

DWG . NO . 

TP1 

C818 

.1UF 

C819 

.01UF 

R817A 

100 

TP2 

R816 

1.0K 1% 

Q803 

2N5087 

200915-SCH 

PROJ NO. 

Z4 

1 2 

R817B 1 

Z5 

2 

2K 

2W 

R822 

22.0K 

* 

* 

C820 

0.01UF DISK 

533 

1 

2 

3 

4 

5 

6 

SHEET 

HD1 

C 7527-2_6 HDR 

P808 

PA-DC OUT 

FASTON TAB 

REV. 

C 

1 OF 1 

E 

DWG. NO. 200915-SCH REV. C 

C 

B 

A

R20 

R19 

Illustration 6-13 Power Amplifier-FM100/FM250 


RF Output Amplifier 

RF OUTPUT AMPLIFIER 

6 - 22

Illustration 6-14 RF Output Filter 


(455MHz) 

(195MHz) (176MHz) (252MHz) 

RF IN 

C1202 

1.35PF 

C1204 

7.1PF 

C1206 

9.3PF 

C1208 

5.13PF 

R1202 

* 75 

C1211 

47PF NP0 

R1203 

10 

RF OUT 

L1201 

250NH 

C1201 

15.4PF 

L1202 

90.5NH 

C1203 

40.9PF 

L1203 

94.1NH 

C1205 

38.9PF 

L1204 

87.5NH 

C1207 

37.7PF 

L1205 

77.9NH 

C1209 

14.1PF 

C1209A 

2PF 

C1219 

47PF SM 

R1204 

10 

R1205 

* 75 

C1201A 

10PF 

C1218 

47PF SM 

INDUCTORS 

C1217 

3.5PF 

R1201 

100 

I.D. 

HD1201 

1 

2 

3 

RF MONITOR 

TURNS 

Approx. 7V RMS 

with 200W RF in. 

LENGTH 

GUAGE 

R1210 

10K 

D1201 

1N6263 

C1213 

.001 

R1206 

1K 

C1212 

47PF NP0 

R1207 

100K 

RFV 

C1214 

.01 

R 

E 

F 

L 

F 

W 

D 

C1215 

.01 

R1208 

20K 

R1209 

1K 

D1202 

1N6263 

C1216 

.001 

L1201 

L1202 

L1203 

L1204 

0.25" 

0.5" 

0.5" 

0.5" 

14 

3 

3 

3 

0.7" 

0.6" 

0.5" 

0.7" 

#17 

#12 

#12 

#12 

D1203 

1N6263 

R1211 

100K 

C1220 

.01 

1 2 3 4 5 

L1205 

* 

0.4375" 

EXACT COIL LENGTHS ARE FACTORY-SET. 

IF NECESSARY, SELECT R1202 FOR 

SWR READING OF 1.1 OR BETTER WITH 

50-OHM LOAD. R1205 = R1202 

R1202,R1203,C1211,D1202,C1216 

ON UNDERSIDE OF CIRCUIT BOARD. 

3 

0.6" 

#12 

NOTES : 

_______ 

_______ 


1/4W, 5% UNLESS OTHERWISE 

SPECIFIED. 

2. ALL CAPACITORS ARE IN 

MICROFARADS UNLESS 

OTHERWISE SPECIFIED. 

3. C1201-1209A,1217 are circuit board pads. 

HD1202 

HEADER 5 

RF Output & Reflectometer 

103209 

RF Output Filter and Reflectometer 

6 - 24

F 

1 2 3 4 5 

6 

7 8 

ADDED TO PWB (200922-PWB-D IN LOCATION 

SHOWN, AND DEPICTED ON COMPONENT MAP. 

C23 

C24 


APPROVALS 


DATE DWN CHK CM PE 

264 M PRODUCTION RELEASE 12-10-03 DW DW DP 

279 

316 

361 

N XU1 WAS 200479-TERM-10 01-29-04 DW DW MH 

O PWB CHG'D TO REV. C 06-14-04 DW DW DP 

P PWB CHG'D TO REV. D 03-22-05 DW DW DP 

F 

.01 

.01 

E 

D 

C 

J1 

RF IN 

C1 

.01 

J3 

1 

1 

R1 

OPEN 

1 

D1 

OPEN 

Vin 

L6 

OPEN 

3 

2 

VR1 

OPEN 

GND 

2 

Vout 

R2 

OPEN 

C2 

OPEN 

3 +5V 

C18 

OPEN 

R4 

R5 

OPEN 

C4 

OPEN 

OPEN 

R3 

OPEN 

2 

3 

C3 

.01 

D2 

OPEN 

1 

C5 

22 

R6 

OPEN 

R17 

51 

R16 

OPEN 

XU1 

MHW6342T 

IN 

GND 

GND 

N/C 

VCC 

N/C 

GND 

GND 

OUT 

C22 

OPEN 

L1 

33uH 

R8 

* 

1 

2 

3 

4 

5 

6 

7 

8 

9 

C6 

0.01 

T1 

R18 

C7 

0.01 

L2 

OPEN 

FOR FM30: 

20VDC INPUT APPLIED HERE. 

0 

R7 

OPEN 

Q1 

BLF245 

G 

C8 

OPEN 

L7 

OPEN 

R9 

51 

1/2W 

C16 

0.01 

D 

S 

L4 

10.4uH 

L3 C10 

10pF 

C20 

OPEN 

+24VDC 

C9 

OPEN 

R11 

4.7K 

R10 

10K 

C11 

36pF 

C21 

OPEN 

R12 

OPEN 

D3 

1N753A 

6.2V 

L5 

23.2uH 

C12 

36pF 

C13 

5pF 

FOR FM100 AND FM250: 18V 

FOR FM500: 20V 

C15 

680pF 

C14 

27pF 

R13 

OPEN 

J2 

RF OUT 

FOR FM30: FEED POINT FROM PWR. REGULATOR PWB. 

T 

RT1 

2.7K NTC 

OPEN 

C17 

0.01 

E 

DWG. NO. Q43310-4 REV. P 

C 

B 

A 

B_L_SHT1_A.DOT REV. A 

J4 

1 

C19 

OPEN 

J5 

1 

3 

2 

8 

4 

R15 

OPEN 

R14 

U2A 

OPEN 

1 

OPEN 

R8 POWER LEVEL CONFIGURATION 

FM30 FM100 FM250 FM500 

OPEN 3 OHM 5W 3 OHM 5W 2.7 OHM 5W 

UNCONTROLLED 





5 

6 

U2B 

7 

OPEN 


THESE DRAWINGS AND SPECIFICATIONS ARE THE PROPERTY OF 


AND ARE NOT TO BE REPRODUCED, COPIED OR USED AS THE BASIS 

FOR THE MANUFACTURE OR SALE OF APPARATUS OR 


SCALE : NONE 

1 2 3 4 5 

6 7 8 

NOTE: 

1. ALL RESISTORS ARE IN OHMS, 1/4 WATT +/- 5% TOL. 


DWN 

CHK 

CM 

PE 

FILENAME: 

APPROVALS 

DW 08-28-03 

DW 10-30-03 

DP 10-30-03 

DISTRIBUTION 

TITLE: 

SIZE 

B 

IREC 



574-262-8900 WWW.IREC1.COM 

FM RF DRIVER 

DWG . NO . 

Q43310-4 

PROJ NO. 

533 

SHEET 

REV. 

P 

1 OF 1 

B 

A

3 

t 

t 

1 

1 

x 

x 

x 

3 

2 

1 

3 

2 

1 

8 

6 

4 

2 

1 

2 

3 

4 

5 

6 

x 

x 

x 

9 

7 

5 

3 

1 

x 

x 

x 

1 2 3 4 5 6 DWG. NO. 

REV. 

8 9 10 11 12 

201069-SCH 

A 



DATE 

DWN 

A PRODUCTION RELEASE 

04-04-05 DW 

APPROVALS 

CHK CM 

PE 

DP 

H 

H 

BATTERY IN 

CB1001 

CIRCUIT BREAKER 

ON 

MOTHER BOARD 

G 

PL1002 

PA FAN 

TO 

MOTHER BOARD 

PL1004 

TEMP SENSE 

10 

HD505 

RF DRIVER 

HD502 

TO 

MOTHER BOARD 

20 C0ND. RIBBONCBL 

TO 

MOTHER BOARD 

HD503 

VOLTAGE REGULATOR 

G 

F 

M1HD-S RF POWER AMP 

RF IN 

PL1005 

PL1001 

BNC 

1 

2 

3 

4 

5 

RF OUT 

RF IN 

DRVR V+ 

J4 

1 

LP FILTER 

DRVR V+ 

-12V 

+12V 

HD702 

6 

5 

4 

3 

2 

1 

x 

x 

x 


HD701 

HEADER 6 

HD4 


P1 

+UNREG 

C1001 

15,000UF/110V 

HD703 

1 

2 

3 

FAN 

F 

E 

RF OUT 

RF IN 

RF OUT 

RF OUT 

R1003 

2K 3W 

+ 

E 

HD1 

P805 

1 

1 


P807 

GND 

P804 

1 

D 

1 

P806 

GND 

P803 

1 

D 

1 Z3-2 

P808 

1 

PA DC OUT 

P802 

P801 

1 

1 

POWER REGULATOR 

CORCOM 

6EDL4CM 

C 

120/240 VAC 

50/60HZ 

NEUTRAL 

FILTER 

NOT USED 

H 

220 

100 

240 

120 

F 

E 

D 

MOV 

MOV 

NTC 

NTC 

T1001 

4 

D1001 

2 

S1002 

ON 

C 

HOT 

C 

B 

BRIDGE 

CARRIER 

A 

OFF 

* 

SEE CHART 

G 

S1002 

ON 

B 

A 


* 

VOLTAGE 

120V 

200V 

220V 

240V 

FUSE SIZE 

6.3A 

3A 

SLO-BLO FOR ALL APPLICATIONS 

UNCONTROLLED 










1 2 3 4 5 6 7 8 9 10 11 12 

FILENAME: 

OFF 

POWER 

APPROVALS 

DWN 

CHK 

CM 

PE 

DW 

DW 

DP 

04-04-05 

04-04-05 

04-04-05 

DISTRIBUTION 

K 

IREC 




TITLE: 

SIZE 

C 

SCH, FM CHASSIS INTERCONNECT 

SCALE : NONE 

DWG . NO . 

201232-SCH 

PROJ NO. 

533 

SHEET 

OF 

REV 

A 

B 

A

Section 7—Service and Support 

We understand that you may need various levels of support or 

that the product could require servicing at some point in time. 

This section provides information for both of these scenarios. 

Service and Support 

7–1

7.1 Service 

The product warranty (see opposite page) outlines our responsibility for defective 

products. Before returning a product for repair or replacement (our choice), call 

our Customer Service department using the following telephone number: 

(866) 262-8917 

Our Customer Service Representative will give you further instructions regarding 

the return of your product. Use the original shipping carton or a new one obtained 

from Crown. Place shipping spacers between the slide-out power amplifier assembly 

and the back panel. 

Please fill out the Factory Service Instructions sheet (page 7–5) and include it with 

your returned product. 

7.2 24–Hour Support 

In most instances, what you need to know about your product can be found in this 

manual. There are times when you may need more in-depth information or even 

emergency-type information. We provide 24–hour technical assistance on your 

product via a toll telephone call. 

For emergency help or detailed technical assistance, call 

(866) 262-8917 

You may be required to leave a message at this number but your call will be 

returned promptly from our on-call technician. 

7.3 Spare Parts 

To obtain spare parts, call Crown Broadcast Sales at the following number. 

(866) 262-8919 

You may also write to the following address: 

Service Manger 

International Radio and Electronics Company, Inc. 

25166 Leer Drive 

Elkhart, Indiana, U.S.A. 46514-5425 


Crown Broadcast Three Year Limited Product Warranty 

SUMMARY OF WARRANTY 

Crown Broadcast, IREC warrants its broadcast products to the ORIGINAL PURCHASER of a NEW Crown 

Broadcast product, for a period of three (3) years after shipment from Crown Broadcast. All products are 

warranted to be free of defects in materials and workmanship and meet or exeed all specifications published 

by Crown Broadcast. Product nameplate with serial number must be intact and not altered in any way. This 

warranty is non - transferable. This warranty in its entirety is the only warranty offered by Crown Broadcast. No 

other warranties, expressed or implied, will be enforceable. 

EXCLUSIONS 

Crown Broadcast will not warranty the product due to misuse, accident, neglect and improper installation or 

operation. Proper installation included A/C line surge supression, lightning protection and proper grounding of 

the entire transmitter, and any other recommendations designated in the Instruction manual. This warranty 

does not extend to any other products other than those designed and manufactured by Crown Broadcast. This 

warranty does not cover any damage to any accessory such as loads, transmission line or antennas resulting 

from the use or failure of a Crown Broadcast transmitter. Warranty does not cover any loss of revenue resulting 

from any failure of a Crown Broadcast product, act of God, or natural disaster. 

Procedure for Obtaining Warranty Service 

Crown Broadcast will repair or service, at our discretion, any product failure as a result of normal intended use. 

Warranty repair can only be performed at our plant facility in Elkhart, Indiana USA or at a factory authorized 

service depot. Expenses in remedying the defect will be borne by Crown Broadcast, including two-way ground 

transportation cost within the continental United States. 

Prior to returning any product or component to Crown Broadcast for warranty work or repair, a Return 

Authorization (RA) number must be obtained from the Crown Broadcast Customer Service Department. 

Product must be returned in the original factory pack or equivalent. Original factory pack materials may be 

obtained at a nominal charge by contacting Crown Broadcast Customer Service. Resolution of the defective 

product will be made within a reasonable time from the date of receipt of the defective product. 

Warranty Alterations 

No person has the authority to enlarge, amend, or modify this warranty, in whole or in part. This warranty is not 

extended by the length of time for which the owner was deprived the use of the product. Repairs and 

replacement parts that are provided under the terms of this warranty shall carry only the unexpired portion of 

the warranty. 

Product Design Changes 

Crown Broadcast reserves the right to change the design and manufacture of any product at any time without 

notice and without obligation to make corresponding changes in products previously manufactured. 

Legal Remedies of Purchaser 

This written warranty is given in lieu of any oral or implied warranties not covered herein. Crown Croadcast 

disclaims all implied warranties including any warranties of merchantability or fitness for a particular purpose. 

Crown Broadcast 


Elkhart, Indiana 46514-5425 

Phone 574-262-8900 Fax 574-262-5399 www.crownbroadcast.com 

Service and support 7 – 3

The following lists describe the spare parts kit available for 

your transmitter. 

For the FM100 and FM250, use part number 

GFMSPARES. The following parts are included: 

Item Quantity 

Fuse, 4A Slo-blo 5mmX20mm 6 

Fuse, 6.3A Slo-blo 5mmX20mm 5 


15A 100V N-CH MOSFET 2 

130V RMS 200V PEAK 6500A ZENER 2 

35A 400V Bridge Rectifier 1 

Diode, BYV72E–150 20A 150V 2 

MOS Gate Driver, 500V IR #IR2125 2 

MOSFET, RF Philips #BLF278 1 

Switching Regulator, 0.75A LM3578AN 2 

NTC, In-rush Current Limiter 2 

EMI Filter, 6A 250V with Fuse 1 

14 Stage Bin Cntr/OSC 74HC4060 1 

These parts are included in the FM30 kit (part number 

GFM30SPARES): 

Item Quantity 


Fuse, 3A Slo-blo 5mmX20mm 5 

15A 100V N-CH MOSFET 2 

130V RMS 200V PEAK 6500A ZENER 2 

35A 400V Bridge Rectifier 1 

Diode, BYV72E–150 20A 150V 2 

MOS Gate Driver, 500V IR #IR2125 2 

Switching Regulator, 0.75A LM3578AN 2 

NTC, In-rush Current Limiter 2 

MRF137 FET PWR XISTOR 1 

EMI Filter, 6A 250V with Fuse 1 

14 Stage Bin Cntr/OSC 74HC4060 1 


Factory Service Instructions 

To obtain factory service, complete the bottom half of this page, include it with the unit, and ship to: 

International Radio and Electronics Company, Inc. 


Elkhart, Indiana, U.S.A. 46514-5425 

For units in warranty (within 3 years of purchase from any authorized Crown Dealer): We pay for 

ground UPS shipments from anywhere in the continental U.S. and Federal Express Second Day service 

from Hawaii and Alaska to the factory and back to you. Expedited service/shipment is available for an 

additional charge. You may ship freight collect (COD for cost of freight) or forward your receipt for 

shipping charges which we will reimburse. We do not cover any charges for shipping outside the U.S. 

or any of the expenses involved in clearing customs. 

If you have any questions about your Crown Broadcast product, please contact Crown Broadcast 

Customer Service at: 

Telephone: (574) 262-8900 

Fax: (574) 262-5399 

Name: Company: 

Shipping Address: 

Phone Number: 

Fax: 

Model: Serial Number: Purchase Date: 

Nature of the Problem 

(Describe the conditions that existed when the problem occurred and what attempts were made to correct it.) 

Other equipment in your system: 

If warranty has expired, payment will be: Cash/Check VISA Mastercard COD 

Please Quote before servicing 

Card Number: Exp. Date: Signature: 

Return Shipment Preference if other than UPS Ground: Expedite Shipment Other 

ENCLOSE WITH UNIT—DO NOT MAIL SEPARATELY 

Service and Support 

7–5

Appendix 

Transmitter Output Efficiency 

RF Power Output-FM 30 

PADC Volts PADC Amps RF Power Efficiency 

27.9 2.16 34 56 

26.2 2.09 32 58 

24.7 2.02 30 60 

22.5 1.91 26 60 

20.2 1.77 22 62 

17.0 1.56 17 64 

14.1 1.34 14 74 

12.6 1.22 10 65 

10.5 1.04 7 64 

8.8 .88 5 65 

6.6 .65 3 70 

5.4 .53 2 70 

Power measurements were made at 97.1 MHz. Voltage and current measurements 

were taken from the unit’s built-in metering. The accuracy of the 

internal metering is better than 2%. Return loss of the RF load was greater 

than –34 dB at test frequency . 

FM30/FM100/FM250 User's Manual 

Appendix–1

Transmitter efficiency output 



31.2 5.72 110 61 

29.6 5.35 100 63 

26.4 4.55 79.4 66 

23.5 3.90 63.1 68 

21.1 3.40 50.1 69 

19.0 2.97 39.8 70 

17.1 2.63 31.6 70 

15.4 2.35 25.1 69 

13.9 2.10 20.0 68 

12.5 1.90 15.8 66 

11.2 1.74 12.6 64 

10.1 1.62 10.0 59 

9.1 1.52 7.9 57 

Power measurements were made at 97.1 MHz. Return loss on the attenuators was 

greater than 30. 



45.6 7.14 275 84 

43.6 6.85 250 83.7 

41.4 6.53 225 60 

39.0 6.19 200 60 

36.5 5.88 175 62 

33.8 5.53 150 64 

31.0 5.02 125 74 

27.7 4.69 100 65 

24.0 4.32 75 64 

19.4 3.84 50 65 

13.5 3.26 25 70 

Power measurements were made at 97.1 MHz . Voltage and current measurements 

were taken from the unit’s built-in metering. The accuracy of the internal metering is 

better than 2%. Return loss of the RF load was greater than –34 dB at test frequency. 

Appendix–2 

FM30/FM100/FM250 User's Manual

A B C 

Glossary 

The following pages define terms and abbreviations used 

throughout this manual. 

Glossary 

G–1

A B C 

AF 

ALC 

AM 

bandwidth 

BCD 

BFO 

BNC 

broadband 

carrier 

crosstalk 

density (program) 

deviation 

DIP 

distortion 

DPM 

EPROM 

exciter 

Audio Frequency; the frequencies between 20 Hz 

and 20 kHz in the electromagnetic spectrum. 

Automatic Level Control 

Amplitude Modulation; the process of impressing 

information on a radio-frequency signal by varying 

its amplitude. 

The range of frequencies available for signalling. 

Binary-Coded Decimal; a digital system that uses 

binary codes to represent decimal digits. 

Beat Frequency Oscillator 

A bayonet locking connector for miniature coax; 

said to be short for Bayonet-Neill-Concelman. 

As used in the FM transmitter, refers to the entire 

audio spectrum as opposed to the spectrum influenced 

by the pre-emphasis; also called "Wideband." 

A continuous signal which is modulated with a 

second, information-carrying signal. 

In FM broadcasting, this term generally refers to 

the interaction between the main (L+R) and the 

subcarrier (L–R) signals as opposed to "separation" 

which generally refers to leakage between left (L) 

and right (R) channels. 

A high average of modulation over time. 

The amount by which the carrier frequency 

changes either side of the center frequency. 

Dual In-line Pins; term used to describe a pin 

arrangement. 

The unwanted changes in signal wave shape that 

occur during transmission between two points. 

Digital Panel Meter 

Erasable Programmable Read Only Memory 

(1) A circuit that supplies the initial oscillator used 

in the driver stage. (2) A transmitter configuration 

which excludes stereo generation and audio 

processing. 

G–2 FM30/FM100/FM250 User's Manual

FET 

frequency synthesizer 

FM 

Field-Effect Transistor 

A circuit that generates precise frequency signals 

by means of a single crystal oscillator in conjunction 

with frequency dividers and multipliers. 

Frequency Modulation; the process of impressing 

information on a radio signal by varying its frequency. 

FSK 

gain reduction 

harmonics 

high frequency 

Highband 

I/O 

LED 

modulation 

MOSFET 

nearcast 

Frequency Shift Keying; an FM technique for 

shifting the frequency of the main carrier at a 

Morse code rate. Used in the on-air identification 

of frequencies. 

The process of reducing the gain of a given amplifier. 

Undesirable energy at integral multiples of a 

desired, fundamental frequency. 

Frequencies in the 3.0 to 30.0 MHz range. 

Frequencies affected by the pre-emphasis. 

Input/Output 

Light-Emitting Diode 

The process by which a carrier is varied to represent 

an information-carrying signal. 

Metal Oxide Semiconductor Field Effect Transistor; 

a voltage-controlled device with high input impedance 

due to its electrically isolated gate. 

A transmission within a localized geographic area 

(ranging from a single room to several kilometers). 

PA 

PAI 

PAV 

pilot 

Power Amplifier 

Power Amplifier Current 

Power Amplifier Voltage 

A 19–kHz signal used for stereo transmissions. 

Glossary 

G–3

A B C 

pre-emphasis 

processing 

receiver 

RF 

SCA 

S/N 

spurious products 

stability 

stereo pilot 

stereo separation 

subcarrier 

suppression 

SWR 

THD 

The deliberate accentuation of the higher audio 

frequencies; made possible by a high-pass filter. 

The procedure and/or circuits used to modify 

incoming audio to make it suitable for transmission. 

An option which adds incoming RF capability to an 

existing transmitter. See also "Translator." 

Radio Frequency; (1) A specific portion of the 

electromagnetic spectrum between audio-frequency 

and the infrared portion. (2) A frequency 

useful for radio transmission (roughly 10 kHz and 

100,000 MHz). 

Subsidiary Communications Authorization; see 

"subcarrier." 

Signal to Noise 

Unintended signals present on the transmission 

output terminal. 

A tolerance or measure of how well a component, 

circuit, or system maintains constant operating 

conditions over a period of time. 

See "pilot." 

The amount of left-channel information that 

bleeds into the right channel (or vice versa). 

A carrier signal which operates at a lower frequency 

than the main carrier frequency and which 

modulates the main carrier. 

The process used to hold back or stop certain 

frequencies. 

Standing-Wave Ratio; on a transmission line, the 

ratio of the maximum voltage to the minimum 

voltage or maximum current to the minimum 

current; also the ratio of load impedance to intended 

(50 ohms) load impedance. 

Total Harmonic Distortion 

G–4 FM30/FM100/FM250 User's Manual

translator 

satellator 

VSWR 

Wideband 

VCO 

A transmitter designed to internally change an FM 

signal from one frequency to another for retransmission. 

Used in conjunction with terrestrial-fed 

networks. 

A transmitter equipped with an FSK ID option for 

rebroadcasting a satellite-fed signal. 

Voltage Standing-Wave Ratio; see "SWR." 

See "broadband." 

Voltage-Controlled Oscillator 

Glossary 

G–5

Symbols 

19–kHz 

level adjustment 5–4 

phase adjustment 5–4 

A 

AC. See power: input 

ALC 3–3, 3–7, 4–8 

altitude 

operating range 1–8 

amperes 

PA DC 3–3, 3–8 

amplifier 

RF 4–13 

bias set 5–7 

antenna 2–10 

mismatch 3–3 

applications 1–3 

audio 

broadband 3–5 

distortion 5–9 

frequency 5–9 

high 3–5 

input connectors 2 - 11, 4–3 

input level 1 - 7, 3–5 

monitor connections 2–13, 4–5 

performance 5–7 

pre-emphasis 3–5 

processing 3–5, 4–9 

wide 3–5 

audio processor 3–6 

adjustments 5–2 

board location 4–3, 4–15 

circuit description 4–3 

indicators 3–5 

input 3–5 

reference drawings 6–4 

B 

backup 

transmitter use 1–4 

bandwidth 

RF 5–8 

battery. See power: input 


Index 

booster 


broadband. See audio: broadband 

C 

cables 

audio input 2–11 

carrier 4–9, 5–8 

automatic turnoff 2–14, 3–8, 5–6, 5– 

10 

frequency 5–8, 5–10 

carrier switch 3–4, 5–5 

Channel. See frequency 

channel. See frequency 

main 5–10 

main into sub 5–10 

sub into main 5–10 

chassis 

circuit 4–14 

circuit boards 

audio processor 4–3, 6–4 

stereo generator 4–5 

circuits 

chassis 4–14 

display 4–10 

metering 4–8 

motherboard 4–9 

part numbering 4–2 

power regulator 4–12 

RF exciter 4–6 


voltage regulator 4–11 

components 

numbering 4–2 

composite 

input 2–12 

input connection 2–12 

output 

adjustment 5–2 

connectors 

audio input 2–11 

audio monitoring 2–13 

composite in 2–12 

remote I/O 2–12, 2–14 

RF input 2–10 

RF output 2–10 

RF output monitoring 2–10 

SCA In 2–12 

XLR 2–11, 4–3 

Index–1

cooling fan 3–3, 3–8 

control 4–9 

coverage area 1–4 

crosstalk 1–7 

measurements 5–9 

current limit 

PA 5–6 

D 

DC. See power: input 

de-emphasis 2–13, 5–2, 5–7 

jumpers 2–13 

delay 

program failure to carrier turnoff 2– 

14, 5–6 

dimensions 1–9 

display 


front panel 3–3, 3–5, 3–7 

modulation calibration 5–6 

distortion 1–7 

audio 5–9 

harmonic 4–5 

E 

emissions 5–8 

exciter. See RF exciter 

configuration 1–4 

F 

fan (PA) 

control 4 - 8, 4–9 

cooling 3–8 

fault 

indicators 4–10 

input 3–8 

lock 3–8 

power 3–8 

servicing 3–8 

SWR 3–8 

temperature 3–8 

FCC guidelines 1–8, 5–8, 5–10 

frequency 

carrier 5–8, 5–10 

measurement 5–4 

pilot 5–8 

receiver 2–8 

response 5–9 

selection 2–5, 5–4 


samples 2–6 

synthesizer 5–10 

frequency synthesizer. See RF exciter 


front panel 

display modulation calibration 5–6 

FSK 1–5, 1–6 

measurement 5–5 

fuses 2–4, 7–4 

G 

gain control 3–5 

gain reduction 4–4 

gain switches 

input 3–6 

H 

harmonic distortion 4–5 

harmonics 5–8 

heatsink 3–8 

highband 3–5 

processing 4–4 

humidity 

operating range 1–8 

I 

I/O connector 1–2, 2–14 

pinout 2–15 

indicators 

audio processor 3–5 

fault 3–8, 4–10 

highband 3–5 

LED 3–5, 3–7, 4–10 

pilot 3–5 

wideband 3–5, 5–6 

input 

audio connections 2–11 

composite 2–12 

fault 3–8 

gain switches 3–6 

program 

fault 2–14 

SCA connection 2–12 

Index–2 


L 

labels 1–10 

LEDs 3–5, 4–10 

line voltage 2–2, 2–3 

lock 

status 4–7 

lock fault 3–8 

M 

metering 1–2 


metering board 


location 4–8 

modulation 2–12, 3–5, 5–3, 5–7, 5–8 

calibration 5–6 

compensator 2–7 

display 3–5 

percentage 3–5, 5–9 

monitor 

audio 2–13, 4–5 

mono 

operation 2–12, 3–6 

motherboard 


multimeter 3–7 

front panel 3–3 

N 

nearcast 


networks 

satellite-fed 1–6 

terrestrial-fed 1–5 

noise 1–8, 3–8 

measurements 5–9 

O 

operating environment 1–8, 2–2 

options 1–3, 1–4, 1–6 

output 

power 1–7, 3–7 

display 3–7 

output filter 4–14 

P 

part numbering 4–2 

parts 

spares 7–2 

performance 

checklist 5–7 

tests 5–10 

pilot frequency 5–8 

pilot indicator 3–5 

power 

AC supply 4–14 

AC voltage selection 2–2 

battery 1–4, 1–8, 2–5 

failure 2–2 

fault 3–8 

input 1–4, 1–8, 2–2, 2–5 

FCC guidelines 5–10 

output 1–3, 1–7, 5–8 

display 3–7 


regulator 


RF 3–3, 3–7 

RF amplifier 4–13 

transformer 4–14 

power switch 3–4 

pre-emphasis 1–7, 4–4, 5–2, 5–7 

curve 2–13 

networks 4–3 

processing 

audio 2–13, 3–5 

control 3–6 

control setting 3–3 

highband 3–5, 4–4 

program failure 2–14, 5–10 

program source 2–11, 3–6 

R 

receiver 

frequency selection 2–8 

option 1–5 

specifications 1–10 

reflectometer 4–14 

regulatory approvals 1–9 

remote control 1–2 

remote I/O 

connector 2–14 

pinout 2–15 

remote operation 2–14 

repair 

warranty 7–3 

RF 

amplifier 4–13 


bandwidth 1–8, 5–8 

exciter 2–6, 2–12 

board location 2–6, 4–6 


Index–3

R (continued) 

S 

input 1–5, 2–10 

output 1–2, 1–5, 1–7, 3–3, 3–7 

impedance 1–7 


tuning 2–7 

safety 1–10 

satellator 


SCA 1–5 

input connection 2–12 

sensitivity 

monaural 1–10 

stereo 1–10 

separation 

stereo 1–7 


service 

warranty 7–3 

Service Instructions 7–5 

spares kit 7–4 

specifications 


transmitter 1–7 

stand-alone 


stereo 

separation 1–7, 5–9 

stereo generator 1–2, 2–13 


board location 4–5 

bypassing 2–12 


subcarrier 5–10 

38–kHz 5–10 

suppression 

subcarrier 1–8 

switches 

carrier 3–3, 3–4, 5–5 

T 

temperature 

fault 3–8, 4–9 

operating range 1–8, 5–10 

PA 3–3, 3–8 

test point 

voltage 3–8 

tests 

performance 5–7, 5–10 

time-out 

program input failure 2–14 

transformer 4–14 

translator 


V 

VCO 4–6 

voltage 

AC selection 2–2 

voltage regulator 3–8 



voltage selection 2–2 

voltmeter 

display 3–8 

volts 

PA DC 3–3, 3–8 

VSWR 1–2, 2–10 

W 

Warranty 7–3 

weight 1–9 

wideband 3–5, 5–6 

X 

XLR connectors 2–11 

input gain 3–5, 3–6 

power 3–4 


stereo-mono 3–3, 3–6 

SWR 3–7 

calibrate 5–5 

fault 3–8 

SWR fault 4–9 

synchronization 4–11 

synthesizer. See RF exciter 

Index–4

Crown Low Power Transmitters - Crown Broadcast

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