Zenith HF-46 Stereo Receivers Models MC7031, MC7041, MC7051 ...

IMPORTANT SAFETY NOTICE
WHEN SERVICING THIS CHASSIS,
UNDER NO CIRCUMSTANCES SHOULD
THE ORIGINAL DESIGN BE MODIFIED
OR ALTERED WITHOUT PERMISSION
FROM THE ZENITH RADIO CORPO­
RATION. ALL COMPONENTSSHOULD
BE REPLACED ONLY WITH TYPES
IDENTICAL TO THOSE IN THE ORIG­
INAL CIRCUIT. SPECIAL COMPO­
NENTS ARE USED TO PREVENT
SHOCK AND FIRE HAZARD. THESE
CRITICAL COMPONENTS ARE SHADED
ON THE SCHEMATIC AND PARTS
LIST FOR EASY IDENTIFICATION.
THIS CIRCUIT DIAGRAM MAY OC­
CASIONALLY DIFFER FROM THE
ACTUAL CIRCUIT USED. THIS WAY,
IMPLEMENTATION OF THE LATEST
SAFETY AND PERFORMANCE IM­
PROVEMENT CHANGES INTO THE
SET IS NOT DELAYED UNTIL THE
NEW SERVICE LITERATURE IS
PRINTED.
TEST
POINTS
SWITCHES
A FM. ANTENNA INPUT
D 1ST. FM. IF. INPUT
F MPX. INPUT
FM IF OUTPUT
G
H FM DETECTOR OUTPUT
K AM IF INPUT
L AM. RF INPUT
M 19KHZ OSCILLATOR OUTPUT
SW 1 SELECTION AM FM PHONO(1) PHONO(2) AUX MIC)
SW 2 TAPE DUBBING (1-> 2 OFF 2->1)
SW 3 TAPE MONITOR (1 SOURCE 2)
SW4 MODE (STEREO MONO)
-
SW5 LOUDNESS (ON - OFF)
SW6 FM MUTE (ON - OFFJ
SW7 HIGH FILTER (ON-OFF)
SW8 LOW FILTER (ON- off)
1W9 DE EMPHASIS ( 25us - 75us)
SW10 SPEAKER (OFF A . B . A+B)
SW 1 POWER (ON- OFF )
1
SW3 TAPE MONITOR SWITCHES
1,5 PLAY BACK (1) RIGHT
2,6 SOURCE RIGHT
3,7 FLAY BACK(2) RIGHT
4,8 COMMON RIGHT
9,11 PLAY BACK(1) LEFT
10,14 SOURCE LEFT
11,15 PL AY BACK(2) LEFT
12,16 COMMON LEFT
SW10 SPEAKER SWITCHES
SW2 TAPE DUBBING SWITCHES
1,5 A— 8 RIGHT
2,6 OFF RIGHT
3,7 B—A RIGHT
4 ,8 COMMON RIGHT
9,13 A - B LEFT
10,14 OFF LEFT
11,15 B-A LEFT
12,16 COMMON LEFT
1,6 OFF RIGHT
2,7 A RIGHT
3,3 B RIGHT
4,9 A+B RIGHT
5,10 COMMON RIGHT
11,16 OFF LEFT
12,17 A LEFT
13,8 B LEFT
14,19 A+B LEFT
15,20 COMMON LEFT
NOTf
1 SELECTOR SWITCH I AM 2 FM 3 PHONCXI) 4. PH0NCX2) 3. AUX 6. MIC 7. COMMON
2 ALL RESISTANCE VALUES IN OHMS KKILOHM M:MEGOHM,ALL RESISTORS 1/4W UNLESS OTHERWISE SPECIFIED
3 UNLESS OTHERWISE NOTED IN SCHEMATIC ALL CAPACITORS IN MFD PF PICOFARAD
4 THERE MIGHT BE SLIGHT CHANGES IN THE ACTUAL SET
3 ALL VOLTAGES ARE DC UNLESS OTHERWISE SPECIFIED, DC VOLTAGES SHOWN ARE MEASURED FROM CHASSIS
WITH NO SIGNAL INPUT, LOUONESS SWITCH IN OFF POSITION. LINE VOLTAGE I20V AC, USING
A HIGH IMPEDANCE DIGITAL MULTIMETER
MODEL MC7051 - SCHEMATIC 50