Transistor Replacement.

11-5835-243-34/EE641-AA-MMl-010/E154

MTT/TO

31S3-4-110-1

spacers.

b. Assembly Removal. Remove the power am-

(4) Solder the 15 tagged wires to terminal posts

plifier assembly from tape transport (para 3-27).

on circuit card.

c. Resistor Removal.

(1) Tag and unsolder wires to resistor ter-

CAUTION

minals.

Alternately tighten connector jackscrews

(2) Removal two screws and resistor from heat

one to two turns each until connector is

sink.

securely seated.

(3) Clean dried silicone compound from heat

(5) Secure connector A9P3 to A9J3 by means of

sink.

jackscrews.

d. Resistor Replacement.

i. Power Amplifier Assembly Replacement.

(1) Apply silicone compound (NSN

Replace power amplifier assembly in cartridge

6850-00-927-9461 ) to base of resistor and place in

recorder (para 3-27).

position.

(2) Secure resistor to heat sink with two screws.

3-29. Capstan Motor Assembly B1

(3) Solder wires to resistor terminals.

(18, fig. 3-7)

e. Transistor Removal.

a. Removal.

(1) Tag and unsolder wires to transistor base

(1) Remove power amplifier assembly A9 (para

and emitter.

3-27).

(2) Remove two screws, nuts, lock washers, flat

(2) Remove harness clamp on tape deck ad-

washers and collector wire terminal.

jacent to motor assembly.

(3) Remove transistor and insulator from heat

CAUTION

sink.

Care must be taken not to damage ex-

(4) Clean dried silicone compound from heat

ternal motor wiring when removing

sink and insulator.

mounting screws.

f. Transistor Replacement.

(1) Apply silicone compound (NSN

(3) Remove four mounting screws (17) and lift

6850-00-927-9461) to both sides of insulator and

out the motor assembly.

place insulator and transistor in position in heat

b. Replacement.

sink.

CAUTION

(2) Secure transistor to heat sink with screws,

Care must be taken not to damage ex-

lock washers, flat washers, nuts and collector wire

ternal motor wiring when replacing

terminal.

mounting screws.

g. Circuit Card (A2) Removal.

(1) Tag and unsolder 15 wires from terminal

(1) Place the motor assembly (18) on the tape

posts.

deck and secure with four mounting screws (17).

Place a drop of sealant on the screw threads before

CAUTION

installing.

Alternately turn connector jackscrews

(2) Secure the cable clamp on the tape deck

one to two turns each until plug separates

adjacent to the motor assembly.

completely from jack.

(3) Install power amplifier assembly A9 (para

(2) Disconnect A9P3 from A9J3.

3-27).

(3) Remove four socket head screw assemblies

that secure circuit card and spacer board to the heat

3-30. Capstan Motor Assembly Brush

sink. A socket screw assembly includes a lock

(fig. 3-9)

washer, flat washer and a fiber spacer located be-

NOTE

tween the circuit card and the spacer board.

The capstan motor has two brush

h. Circuit Card (A2) Replacement.

assemblies; one for the motor and one for

(1) Place spacer board in position on heat sink.

the integral tachometer located at rear of

(2) Line up four fiber spacers above holes in

motor assembly. Replace both brush

spacer board.

assemblies at the same time (para a.

(3) Place circuit card in position on four

through d., below).

3-19