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ALIGNMENT PROCEDURE
FM STEREO ALIGNMENT PROCEDURE
PRECAUTIONS
INSTRUMENTS:
FM Signal Generator, AC VTVM
and Oscilloscope.
NOTE:
The FM IF Amplifier must be completed before attempting this FM-Stereo Alignment. Poor IF alignment will result in poor
Multiplex Adjustment.
Set Separation Adj. VR302 {on MPX board) to max-position before starting this procedure.
Set Selector switch to ''FM STEREO".
Connect Stereo Generator to FM antenna terminals.
)
ADJUST
FOR
MODULATION
RF DEVIATION
2— 5%
Oscilloscope to
L301, 302
Maximum Amplitude
Test Point 5
and 303
on scope.
(on MPX board)
5%
ee
aE
Re
VR301
Stereo Beacon Lamp
just comes on.
Pilot
9%
Oscilloscope and VTVM
L302
Maximum and undis-
Signal 70%
|
to Left channel TAPE
torted sine wave on
OUT jack.
scope.
Oscilloscope and VTVM
Minimum reading on
|
to Right channel TAPE -
VTVM.
OUT jack.
.
Same as in step 3.
Repeat steps 4 and 5 until no further improvement is possible.
And adjust Separation Adj. VR302, if necessary.
FM MUTING ADJUSTMENT
INSTRUMENTS:
FM Signal Generator and Oscilloscope.
Set Selector switch to "FM" position.
OUTPUT
INDICATOR
CONNECTED
TO
Oscilloscope to
TAPE OUT
19KHz Pilot
signal only
Composite
1 KHz signal
to Left
channel only
Composite
1 KHz signal
to Right
channel only
ADJUST
%
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Check output
switch
10 uV
"OF
F''
Turn to Clockwise
until the output
just disappears.
Muting Level
control VR 901
(on chassis)
switch
Freq. Adju. L703
(on Muting circuit
board)
Adjust L703 to obtain
symmetrical output
when detuned upper
and lower side.
Repeat step 2.
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