Instruction manual

7-8

! Warnin

BEFORE PERFORMING ANY OF THE FOLLOWING

TROUBLESHOOTING PROCEDURES, THE PRELIMINARY

TROUBLESHOOTING INFORMATION AT THE BEGINNING OF THIS

“TROUBLESHOOTING” SECTION MUST BE READ, UNDERSTOOD,

AND FOLLOWED.

Procedure A

If the green NORMAL LED is “OFF”, the yellow TROUBLE LED is “OFF”, and no module LEDs

“ON”, a power loss condition has occurred. A power loss condition may be caused by:

1. Loss of AC input voltage and/or battery back-up voltage.

2. Faulty internal wiring between the DCPS (Dual-Circuit Power Supply) module and the

Motherboard (DCMB).

3. Faulty DCPS module.

4. Faulty Motherboard (DCMB).

Perform the following:

1. Check for 24 +/- 5VDC at TB1 on the DCMB. If voltage is not present, perform steps 2

through 5.

2. Remove DCPS Cover. (See Figure 3-16 on Page 3-15) Observe if AC LED and DC LED are

“ON” (See Figure 9-5 on Page 9-9 for locations).

a) If both LEDs are “ON”, inspect wiring and connections between the DCPS

and TB2 on DCMB.

b) If both LEDs are “OFF”, check 120VAC input to DCPS. If AC is not present,

check AC source. If AC is present, replace DCPS.

c) If AC LED is “ON” and DC LED is “OFF”, remove AC Power and Battery Power

from the DCPS, disconnect 24VDC wires from TB2 on DCMB and allow panel to

cool for 20 minutes. Re-apply AC power. If DC LED remains “OFF”, replace

DCPS. If DC LED is “ON”, problem is a high current draw on the DCMB or

DCDC module.

3. Replace the DCDC module.

4. Replace the Mother Board (DCMB) module.

When the trouble is repaired and before testing, mark all wires then replace all wires to the

proper locations and replace all covers

Procedure B

On the Dual-Circuit Control Module (DCDC), if the green NORMAL LED is “ON” and the yellow

TROUBLE LED is “ON”, and D12, D11, D10 are “OFF”, a faulty controller module (DCDC)

condition has occurred. A faulty controller module condition may be caused by:

1. DCDC module inoperable.

Perform the following:

1. Replace the DCDC module.

Procedure C

On the Dual-Circuit Control Module (DCDC), the green NORMAL LED is “OFF”, the amber

TROUBLE LED is “ON”, D12 “OFF”, D11 “ON”, D10 “OFF”, and On the Digital Voice Module

(MDX-2), the green NORMAL LED is “ON”, and the amber SYSTEM TROUBLE LED is “ON”

This condition is caused by: