EFJohnson 3000 SERIES - Manual (Page 168)

MULTI-NET CONSOLE MODULE (MCM)
20-4
20.5 PCM SUMMATION PERSONALITY CARD
The PCM Summation Personality Card sums
multiple time slots on the PCM audio bus for the unse-
lect audio for the VRCM-50 Series of consoles (see
Figure 20-3).
20.5.1 INTERNAL CONNECTIONS
1. Plug the summation card into J32.
2. Plug the summation card into the piggyback bus via
J31.
3. Connect wire harness A3 on the Main Card to the
summation card:
Rx PCM Primary U26, pin 13 to J4, pin 1
Master Clock U26, pin 9 to J4, pin 2
Master Sync U26, pin 7 to J4, pin 3
4. Connect wire harness A2 on the Main Card to the
Summation Card:
M-lead relay K1, pin 1 to UNSEL+ J3, pin 1
M-lead relay K1, pin 4 to UNSEL- J3, pin 2
5. Remove Q12 to ensure the M-lead is inactive.
20.5.2 EXTERNAL CONNECTIONS
The Summed Unselect Audio Output is on the
MA and MB external connections.
The Summed Select Audio Output is on the
Primary Tx+ and Tx- connections.
20.5.3 ALIGNMENT PROCEDURE
1. Set CIM S5 to Test 9
(open section 1-4, close 2-3).
2. Unselect audio adjust:
a. Set MCM S5 to Test 9 (open section 1-4,
close 2-3).
b. Press S2 on the MCM and release.
c. Adjust R36 for 4.0V P-P
±
0.25V at TP1 on the
summation card using an oscilloscope.
(Alternate method: Use the transmission test set
and adjust R36 for -22.0 dBm
±
1 dB).
d. Adjust R37 for -3 dBm at TP2 on the PCM
summation Card.
3. Select Audio adjust:
a. Set MCM S5 to Test 10 (open section 2-4;
close 1-3).
b. Press S2 on the MCM and release.
c. Adjust R38 for 4.0V P-P
±
0.25V at TP3 on the
summation card using an oscilloscope.
(Alternate method: Use the transmission test set
and adjust R38 for -23.0 dBm
±
1 dB).
d. Adjust R39 for -3 dBm at TP4 on the PCM
Summation Card.
4. Set S5 on CIM and MCM (all sections closed).
5. Reset each module, press S2 and release.