Sanyo M7700L - FM MPX Alignment

FM MPX ALIGNMENT
se Alignment
ALL IC FO
(19 kHz)
Adjustment
TUNER ADJUSTMENT (continuea)
Standard test frequency 400 Hz and deviation 75 kHz
Connections
Tuning Dial Adjustment
None
OUTPUT
Connect frequency counter
or synchro-scope to No. 12
pin of IC (LA AN7410).
FM Stereo
Signal
Separation
Connect Stereo SG to
antenna terminal.
Main channel signal
of StereoSG —— ON
Pilot (19 kHz) and Sub
channel signals of
Stereo SG —— ON
L channel and Pilot
(19 kHz) signals of
Stereo SG —— ON
Connect VTVM with
3.2 ohm dummy load.
distortion meter, and
oscilloscope to R channel
Ext. speaker terminal.
Setting
Obtain 19 kHz on the frequency
counter or synchro-scope.
Maximize amplitude and VTVM
reading.
Tuning Dial
Minimize distortion meter reading
with maximum amplitude.
Minimize amplitude and VT VM
reading.
Main channel signa!
of StereoSG —— ON
Pilot (19 kHz) and Sub
channel signals of
Stereo SG —— ON
R channel and Pilot
(19 kHz) signals of
Stereo SG —-— ON
Connect VTVM with
3.2 ohm dummy load,
distortion meter, and
oscilloscope to L channel
Ext. speaker terminal.
Repeat the above adjustments.
e Use a screwdriver with plastic grip for all adjustments.
5. Re-connect the measuring instruments to external speaker 6.
jack and adjust the tuning knob and the potentiometer (P2)
following the next chart.
i=
Maximize amplitude and VT VM
reading.
Tuning Dial
Minimize distortion meter reading
with maximum amplitude.
Minimize amplitude and VTVM
reading.
Repeatedly perform the adjustments in Items 5 and 6 to
minimize the signal leakage for both right and left channels.
Then, reduce the difference between each channel
separation by adjusting the potentiometer (P2).