DECODER ALIGNMENT
ADJUST
67KC Trap (L-6)
T-6 top and
bottom;
L-5
T-7 bottom core
T-7 top core
L-5
MPX light adjust
control R-12
TEST
LIMITS
Adjust for mini-
mum voltage
Adjust for maxi-
mum voltage
SAME
Adjust for stable
scope display
30db separation
or more
SAME
REMARKS
Stereo light must be on. This is done by adjusting the "MPX Light
control, R-12.
Adj."
Stereo light must be off.
• ~
Stereo light must be completely on.
1. Turn off 19KC pilot on MPX generator.
2. Adjust upper core of T-7 to obtain a stable and uniform 1 KC signal
scope display. This adjustment may be critical, so turn core very
slowly.
3. Turn 19KC pilot back on.
Modulate left channel and measure right channel output. Adjust L-5 for
minimum right channel output (maximum separation). Be sure all test
leads are removed from TP#2 for separation tests.
Modulate right channel and measure left channel output. Separation in
steps 5 and 6 should be at least 30db.
This step checks the rejection of 19KC and 38KC frequencies. Residual output should be
at least 40db below modulated output.
Turn control until light comes on. Then back off just enough to cause
the light to go off. Then back off about 1/8 of a turn more. Light should
operate ONLY on a MPX signal.
5
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