McIntosh MX 110

DECODER ALIGNMENT
ADJUST
TEST
LIMITS
REMARKS
67KC trap Adjust for
minimum voltage
1 9KC phase coil
and
1 9KC transformer
1. Disable local 38KC oscillator by placing a jumper wire across 6.8K resistor connected to pins
1 and 6 of 12AU7 MPX oscillator.
2. Shunt pin 2 of 19KC transformer to ground with .01 capacitor in series with 1 K resistor.
3. Adjust 19KC phase coil for maximum output. Proper adjustment places core approx. %"
from bottom of coil form.
4. Adjust lower core of 19KC transformer for maximum output.
5. Shunt pin 3 of 19KC transformer to ground with .01 capacitor in series with 1 K resistor.
6. Adjust upper core of 19KC transformer for maximum output.
7. Remove jumper used in step 1 above.
38KC transformer
bottom core
Adjust for
maximum voltage
38KC transformer
upper core
Adjust for
stable scope
display
1. Turn off 19KC pilot on MPX generator.
2. Adjust upper core of 38KC transformer 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.
19KC phase coil 30db separation
or more
Modulate left channel and measure right channel output. Adjust 19KC
phase coil for minimum right channel output (maximum separation).
Remove all test leads from TP #2 for separation checks.
SAME
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.
1 ' ' .
Check for MPX indicator light
1. MPX light should turn on with MPX signal
2. Tuning slowly across dial, MPX light should turn on only with MPX signal.