MULTI-NET CONSOLE MODULE (MCM)

20.5 PCM SUMMATION PERSONALITY CARD

The PCM Summation Personality Card sums

multiple time slots on the PCM audio bus for the unselect 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.

20-4