TEST POINTS
A;
FM ANTENNA INPUT
D; 1st
FM F
INPUT
G;
2ND
FM IF
OUTPUT
H; FM DETECTOR OUTPUT
L;
AM.
RF.
Si IF
INPUT
M;
I9KH2 GAIN
K;
AM
IF
INPUT
CONTROL
R403
BALANCE
R405
VOLUME
R411
TREBLE
R4I7
BASS
SWITCHES
S
50I
POWER
(ON -OFF)
SI
FUNCTION SELECTOR
[AM
FM
PHONO AUX
]
S2
AFC (ON -OFF)
S3
MUTING (ON-OFF)
S4
LOUDNESS (ON-OFF)
95
MODE
(
MONO
-
STEREO)
S6
HIGH FILTER (ON-OFF)
S7
LOW FILTER (ON-OFF)
S8
MONITOR (TAPE
-
SOURCE)
S9
SPEAKER (OFF
-
A.B.A+B)
SIO
DE-EMPHASIS
(
75us-
25uS>
AF BOARD TRANSISTORS
NO
DESCRIPTION
QI40I, I45I DIFF AMP
QI402, I452
CURRENT SOURCE
Q1403, I453
BIAS
Q1404,1454
DlFF
AMP
QI405,1455 PRE DRIVER
Q1406,1456 BIAS
Q1407,1457
PROTECTOR
Q1406,1458
PROTECTOR
!1409,1459 DRIVER
QI4I0,
1460 DRIVER
Q1411,
1461 OUTPUT
Q1412 ,1462
OUTPUT
NOTE
l_ ALL RESISTANCE VALUES IN OHM K! KILOHM M:MEGOHM
THE WATTAGE OF RESISTORS NOT SPECIFICALLY DESIGNATED IS I/4 WATT.
2 UNLESS OTHERWISE NOTED IN SCHEMATIC ALL CAPACITORS IN MF
PF * PICOFARAD
3. THERE MIGHT BE SLIGHT CHANGES IN THE ACTUAL SET
4 ALL VOLTAGES ARE DC UNLESS OTHERWISE SPECIFIED
DC.
VOLTAGES SHOWN ARE MEASURED FROM CHASSIS,
WITH NO SIGNAL INPUT, LOUDNESS SWITCH IN "OFF" POSITION
LINE VOLTAGE I20V AC USING A HIGH IMPEDANCE
DIGITAL MULTIMETER
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.
IC VOLTAGES
IC 30I
PIN
MONAURAL,
STEREO
I
11.45 12
2
3.2
3.I
3
5.5 5.2
4
9.0
9.3
5 9.0 9.3
6
I5.7 0.7
7 0 0
8 0.07
2.4
9 2.4
2.37
IO
1.56 1.56
II
2.2
2.4
12 2.4 2.4
13
2.4
2.4
14
3.3
3.3
NOTE
-
SEE
PARTS LIST
FOR
PRODUCTION CHANGES
SWITCH:
POSITIONS
CONNECTIONS
1.
AM.
(SHOWN) 5
-
1
2
FM
5 -2
3. PHONO 5-3
4. AUX 5-4
PRINTtD CIRCUIT SWITCH NOTES
ARROW INDICATES MOVEMENT
OF
WIPER CORRESPONDING
TO CLOCKWISE ROTATION
OF
SHAFT
SWITCH CONTACTS HAVE BEEN ASSIGNED ALPHANUMERIC)
DESIGNATIONS
TO
ASSIST SERVICE TECHNICIANS
IN
CIRCUIT TRACING.
MODEL MC7041
-
SCHEMATIC
46
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