Marantz 2015 - Audio Adjustment

2. Modulate the FM SG with stereo composite signal consisting of subchannel signal only (of
course a pilot signal must be included).
Adjust
the
core
of
L110
for
maximum
audio
output,
then,
modulate
the
FM
SG
with
a
stereo
composite
signal
consisting
of
L
or
R
channel
only,
and
adjust
the
trimming
resistor
R161
for
maximum
and
equal
separation
in
both
channels.
9.2 Muting Circuit Alignment
1. Set the FM SG output to provide 25 nV (IHF) at 98 MHz and tune the receiver to the same
frequency.
Adjust the trimming resistor R153 for the threshold level of 25 »V (during this adjustment
turn the MUTING pushswitch ‘’on’’).
10. Audio Adjustment
1. Connect a VTVM across the resistor R647 and adjust the trimming resistor R627 until the
VTVM reads 7.5 mV DC.
For the other channel connect the VTVM across the R648 and adjust the R628 for the same
reading.
2. Connect a oscilloscope across the speaker terminals. Apply an audio signal of 1 KHz to the
AUX jucks and increase the audio signal until the audio output on the scope begin to start
clipping. ;
Adjust the trimming resistor R615 for equal and symmetrical clipping.
For the other channel adjust the R616.
POINTER
Figure 1. Dial Stringing