REMOVING AND REPLACING PRINTED CIRCUIT BOARDS A6, A7, A8, A9

TM 11-5805-387-34-2

2-10. REMOVING AND REPLACING PRINTED CIRCUIT BOARDS A6, A7, A8, A9

NOTE

When board A6 must be removed, unsolder diodes CR1 and CR4 connections at board terminal 5

in addition to the procedures below.

REMOVE

Detach and swing front panel away from chassis (para 2-9). Remove compartment cover.

Remove six screws holding circuit board A6 and circuit board A8 to compartment housing..

Remove three screws holding circuit board A9 to compartment housing.

Remove three screws holding cover on circuit board A7 and then remove three hex nuts holding circuit

board A7 to compartment housing.

Lift printed circuit board out of compartment to gain access to all terminals on the board.

Tag and unsolder all wires connected to board terminals.

Remove board.

REPLACE

Solder all wires to the terminals of the replacement board. Be sure to connect each wire to the proper

terminal. For board A6, be sure to connect diodes CR1 and CR4 to terminal 5.

Carefully insert board into it's compartment. Be sure that all wires are out of the way.

Replace screws (or hex nuts for board A7) to secure board to compartment housing.

Replace screws to secure cover to board A7.

Reattach front panel to chassis (para 2-9)

2-11.

REMOVING AND REPLACING POWER TRANSISTORS Q1, Q2, Q3

REMOVE

Detach and swing front panel away from chassis (para 2-9). Remove compartment cover.

Tag, unsolder and remove all wires from transistor.

Remove nuts, lockwashers, nylon bushing, screws holding transistor to compartment housing.

Remove transistor.

NOTE

Do not remove mica insulator unless it is damaged.

REPLACE

Replace mica insulator if it is damaged. Apply a coat of Grease, Laboratory Stock (NSN 9150-00-598-

7445) on mounting surface area before placing mica insulator in position.

Position transistor on compartment housing.

Replace screws, nylon bushing, lockwasher, nuts.

Solder wires to transistor terminals.

Reattach front panel to chassis (para 2-9).

2-29