Table 2-6. Troubleshooting of Laser Power Supply Control C-9135/VVG-1 (A77)--Continued

TM 9-1240-369-34

Table 2-6. Troubleshooting of Laser Power Supply Control C-9135/VVG-1 (A77) - Continued

Item

No.

Malfunction

Probable cause

Corrective action

indicates +0.2 0.2 V with proper

Improper readout on RANGE

RANGE (METERS) indicator

range selection. continue with step 11.

If multimeter indicates+4.0 1.5 V, with

when RANGE RETURN

is selected continued

proper range selection. continue with

step 22.

11.

Using multimeter measure voltage at

pin 5,6, or 8 of A77A3 card. If

multimeter indicates +4.0 1.5 V, with

proper range selection. replace A77A3

card and continue with step 17.

If multimeter indicates +0.2 0.2 V

with proper range selection return A77

unit to depot for repair.

12.

Disable switch S1and interlock switch

S1 on chassis.

13.

Remove A77A5 card (para 3-5c).

14.

Install extender card 13, table 2-1)

15.

Insert A77A5 card into extender

card connector.

16.

Enable switch S1 and interlock switch

S1 on chassis.

17.

Perform step 3 and continue with

step 18.

18.

Using multimeter, measure voltage at

pin 20, 21, or 22 of A77A5. card. If

multimeter indicates +0.2 0.2 V with

proper range selection, replace A77A5

card and continue with step 19. If

multimeter does not indicate

+0.2 0.2 V with proper range return

selection, return A77 unit to depot for

repair.

19.

Disable switch S1 and interlock switch

S1 on chassis.

20.

Remove extender cards.

21.

Install A77A3 and A77A5 cards (para

3-5c) and continue with step 24.

22.

Remove extender card.

23.

Install A77A3 card (para 3-5c)

24.

Remove unit from hot mock-up.

25.

Purge unit (TM 9-2350-230-12).

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