ELECRAFT K2 - TR External Relay Driver using the 8R Line ... - N0SS

IMPORTANT BUILDERS'S NOTICE
MARCH 27, 2011
This notice effects only K2 External T-R Driver kits sold after 26
March, 2011.
Due to a change in the minimum quantity (1,000 ) I must order of the 2-pin
housings (J2) for this kit, I have been forced to use a different connector
for J2. Instead of the 2-pin housing shown in the illustrations, you will
now find a 2-pin header receptacle which has been pre-wired for your
convenience.
The wires used on the new J2 connector are LIGHT and DARK and
should be easily identified as to their difference. The LIGHT wire will be
either white or yellow, while the dark wire will be either black or green.
For the sake of building this kit, always use the LIGHT-colored wire for the
+T-R KEYLINE and the DARK-colored wire for the GROUND.
When you attach J2 to the PC board the LIGHT-colored wire will the
inner-most wire of the two when plugged into P2 on the PC board.
J2 - Pre-wired.
Plug contact &
lighter colored
wire are +TR.
P1
J2
P2
R1 10k
IRF610B
IRF620
G D S
If you happen to reverse this connector, the only thing that will happen is
that your amplifier will key continuously (once power has been applied to
it), until you reverse the plug on P2. So no harm should come to either
your K2 or to your amplifier.
I apologize for this change in the components, but I cannot afford to order
1,000 connectors in order to assemble my remaining 40 kits.
Q2
Q2 (alt.)
Q1
R3 100k

1
ELECRAFT K2 - T-R External Relay Driver
using the 8R Line and J13
Tom Hammond NØSS v2.4 14 MAR 2011
V1.8 1/4w NØSS
24SEP06
P2
P1
K2 Ext T-R Rly Drvr
Bend
Here
8R
(P1-1)
FIGURE 3
IRF610B
R2
100k
P1 mates with J13
on K2 RF board
FIGURE 1 - PC BOARD
As viewed from the
BOTTOM of the board
Q2 - IRF610B or equiv.
0.175-0.20 in.
(4.4-5.0mm)
Q1
2N7000
0.175-0.20 in.
(4.4-5.0mm)
Bend
Down
90°
P1
J2
P2
R1 10k
FIGURE 5 - Q2 Lead Bending Detail
G
P1 preparation.
Slide plastic
carrier down
on pins.
3/32" (2.4mm)
+6VDC
(P1-8)
D
S
GND
(P1-2&4)
R1
10k
J2 - Pre-wired.
Plug contact &
lighter colored
wire are +TR.
SCHEMATIC
R3
100k
Q2
IRF620
or equiv.
G
D
S
GND
(P1-2&4)
Q2
IRF610B
IRF620
G D S
Q2 (alt.)
P2-1
P2-2
Q1
R3 100k
FIGURE 2 - PARTS LAYOUT
As viewed from the TOP
of the PC board
Foil side of
PC board
J2
Open Drain Output
(pulled to GND on TX)
NOTE: If you do not need to
be able to key voltages more
than +50VDC or currents
over 150mA, you may replace
Q2 with Q2 (alt.) (2N7000) at
the location shown below. Q2
(alt.) is NOT included in this kit.
Q1
Q2 (alt.)
2N
7000
S G D
P1 P2
FIGURE 4 P1 & P2
Installation
Light(er) colored wire
+T-R
GND
FIGURE 6 - J2 Wiring
Q2
IRF610B
IRF620
G D S

RCA jack
for K2 T-R
output
BNC jack
for K160RX
(if installed)
K2 T-R Relay Driver PC board installed in a K2.
K2 8R-Line External Amp. T-R Control Adapter
PARTS LIST
Part ID Description Mouser #
Q1 2N7000 MOSFET 512-2N7000
Q2 IRF620 MOSFET (200VDC, 6A max.) or 511-IRF620
IRF610B MOSFET (200VDC, 3,3A max.) or 512-IRF610B
2N7000 MOSFET (60VDC, 200mA max.) 512-2N7000
R1 10k 1/4w carbon film resistor (Brn-Blk-Org) 660-CF1/4C103J
R2,R3 100k 1/4w carbon film resistor (Brn-Blk-Yel) 660-CF1/4C104J
P1 8-pin header, "long post" male header 517-834-03-36
J13 8-pin single-row recept., installs in K2 RF-J13 517-974-01-36
P2 2-pin rt-angle header 538-22-28-8020
J2 2-pin housing 538-22-01-2027
Misc Crimp Terminals for 2-pin housing (2 req.) 538-08-50-0114
Misc Phono jack, panel-mount 161-1002