Inverter Drive Circuit Board A1A2 Testing and Repair

TM 11-6130-377-14

(10) Reach in through the forward opening in

(1) Open the front indicator panel to gain

the left side panel and carefully lift the heat sink

access to the inverter drive circuit board (fig. 2-1 and 2-

assembly and bring it out of the tunnel.

2).

(11) Tag the electrical leads and components

(2) Remove connector A1P1 and code plug

attached to the terminals of SCR A1Q2 for proper

A1P2 from the serviceable inverter drive circuit board.

reassembly. Remove the electrical leads from the SCR

(3) Remove four screws securing the inverter

A1Q2.

drive circuit board to the heat sink cover and remove

(12) Remove the nut and lockwasher securing

inverter drive board.

the SCR to heat sink No. 2 and remove SCR A1Q2.

(4) Remove ten screws securing the heat sink

(13) Install replacement SCR into mounting

cover to the heat sink and remove cover to gain access

hole of heat sink No. 2 and secure using lockwasher

to connector A1P3. Disconnect A1P3 (para 6-8).

and nut.

(5) Cover the lower front chassis area of the

(14) Install

the

electrical

leads

and

inverter with a rubber mat or suitable insulating material.

components on the terminals of the SCR A1Q2.

(6) Install connector A1P1 and code plug

(15) Slide heat sink No. 2 into the heat sink

A1P2 to the inverter drive circuit that is to be tested and

duct tunnel and align the mounting holes of the tunnel

place the board on the insulating material.

and the stand-offs. Secure with lockwasher and bolts.

(7) Connect the variable DC source DDC

(16) Install the screen on the mounting

2592, or equivalent, to the input terminals of A1TB1 (fig.

brackets of the heat sink exhaust.

6-2).

(17) Connect electric lead (wire No. 49) to the

(8) Pull out the plunger of the door interlock

anodes of diodes A1CR6 and A1CR7.

switch A1S1 to enable the inverter to operate with the

indicator panel open.

(18) Position the heat sink duct cover on the

heat sink duct and align the mounting holes.

NOTES

(19) Install the ten screws, lockwashers, and

1. The inverter drive circuit board

flat washers in their respective holes and tighten screws.

is coated with acrylic lacquer;

(20) Position inverter drive circuit board A1A2

therefore, it may be necessary to

on the standoffs of the heat sink duct cover and align

scratch the various components or

the mounting holes.

leads to make a good electrical

(21) Install four screws and lockwashers and

contact

before

attaching

test

tighten screws.

equipment.

(22) Connect plug A1P1 to its receptacle

2. When touching transistor leads,

A1A2J1 on the inverter drive circuit board A1A2.

make certain no other surface is

(23) Close front indicator panel and secure the

touched.

four captive screws.

3. Turn off the dc input source

(24) Perform equipment verification (para 6-

BEFORE making test equipment

22) to check for proper performance.

connections.

6-9.

Inverter

Drive

Circuit

Board

A1A2,

6-10.

Inverter Drive Circuit Board A1A2 Testing

Preliminary Procedure for Testing and

and Repair

Repair

Upon completion of each fault isolation and repair,

The inverter drive circuit board A1A2 can be tested and

reinstall the inverter drive circuit board into the inverter

repaired by electrically attaching it to an inverter in a

and perform a functional verification of the unit

known operable condition. In this setup the power static

operation per paragraph 6-22. Connect the equipment

inverter acts as a test fixture when used in conjunction

as described in paragraph 6-8 to perform the following

with the variable DC source DDC 2595 (or equivalent).

tests.

a. To install the inverter drive circuit board into the

inverter and prepare for checkout, proceed as follows:

Change 1

6-10