Marantz 112 - Test Equipment Required for Servicing

(3) Adjust the trimming resistor R289 for maximum and same separation in both channels.
5.2 Muting Circuit Alignment
Set an FM signal generator (FM SG) output to provide 12.5uV (IHF) at 98MHz and tune
the receiver to the same frequency.
Adjust the trimming resistor R246 for the threshold level of 12.5uV (during this adjustment
turn the MUTING pushswitch ‘‘on’’).
5.3 FM Dolby Level Adjustment
(1) Modulate an FM signal generator to 40% with a 400Hz signal and set it to 98MHz at
1KuV. Precisely tune the tuner to the same frequency.
(2) Depress the FM Dolby pushswitch in. Adjust RSO3 and RS0O4 until the outputs of both
channels may become 340mV.
6. TEST EQUIPMENT REQUIRED FOR SERVICING
Table 1 lists the test equipment required for servicing the Model 112 Tuner.
AM
Signal
Generator
Signal
source
for
AM
align
ment.
|
Tet
Loop
|
«sed
with
AM
Signal
generator.
ment.
Less than 0.3% distortion. Stereo separation alignment
and trouble shooting.
(VCO).
Audio
Oscillator
Weston
Model
CVO-100P,
less
|
Sinewave
and
squarewaves
sig-
than 0.02% residual distortion | nal source.
is required.
zontal and vertical amplifiers. ble shooting.
PCircuitTester | SSS _:CTrouble shooting.
Table 1. Test Equipment Required for Servicing