Table 2-7. Troubleshooting of Battery Power Supply PP-6607/VVG-1 (A78)

TM 9-1240-369-34

Item

No.

Malfunction

Probable cause

Corrective action

WARNING

Ensure that power is off when installing or removing units in hot-mock-up, or installing or removing

components or assemblies in units. The storage battery assembly A78B1 can supply enough short-circuit

current to generate temperatures high enough to cause metal to fuse together, and also cause severe burns

to the human body. When handling the battery assembly remove all rings front fingers and do not insert

metal objects into the immediate area of the battery assembly.

NOTE

Extender card test points are connected to corresponding circuit card pin numbers.

When LASER MODE CONTROL

Power control electronic component.

Install failed unit in hot mock-up.

switch (unit A79) is turned to

assembly card A78A2. Or A78

Perform portion of Checkout

TEST or ON position, no

unit

(para 4-2a or 4-2b) which will

switches or indicators (unit

duplicate malfunction

A75, or A79) illuminate.

3. Remove A78A2 card (para 3-7b).

4. Install extender card (15, table 2-2).

5. Insert A78A2 card into extender card

connector.

6. Perform step 2 and continue with step

7. Using multimeter, measure voltage at

pin 17 of A78A2 card. If multimeter

indicates +24.0 1.0 V, return A78 unit

to depot for repair. If multimeter does

not indicate +24.0 1.0 V, continue

with step 8.

8. Using multimeter, measure voltage at

pin 25 of A78A2 card. If multimeter

indicates +24.0 1.0 V, replace A78A2

card and continue with step 9. If

multimeter indicates +0.2 0.2 V,

return A78 unit to depot for repair.

9. Remove extender card.

10. Install A78A2 card (para 3-7b).

11. Remove unit from hot mock-up.

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

A "1"' is displayed on the right

Battery charge sensor circuit card

1. Install failed unit into hot mock-

hand RANGE (METERS)

assembly A78A3, charge control

up.

indicator (unit A79).

circuit card assembly A78A4

2. Perform portion of BIT (para 4-2a)

power control circuit card

unit which will duplicate malfunction.

assembly A78A2, or A78

3. Remove A78A3 card (para 3-7b)

4. install extender card (13, table 2-2).

5. Insert A78A3 card into extender card

connector.

6. Perform step 2 and continue with step

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