Motor and Tachometer Commutator

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

MTT/TO

31S3-4-110-1

3-34. Front Panel Controls and Indicators

(4) Remove magnetic head assembly PU1 (para

(fig. 3-7)

3-31). Save head shims if any are used.

(5) Remove line filter FL1 (para 3-26).

a. Removal.

(6) Remove interface connector J2 (25) from

(1) Remove six socket-head screws (2) securing

rear of chassis by removing four screws (26),

front panel assembly (3) to chassis.

washers (24) and nuts (23).

(2) Carefully lay front panel assembly down flat

(7) Remove tape deck assembly A8 (para 3-32).

to expose rear side.

(8) Tag and unsolder harness wiring from

(3) Tag and unsolder leads from components

phototransistor assemblies (A8A1, A8A2, A8A4)

being removed.

LED assemblies (A8A3, A8A5) and interlock

(4) Remove component from panel as follows:

switches (A8S1, A8S2).

(a) LED socket is removed by unscrewing nut

(9) Unsolder harness wiring (32) from front

securing socket to panel.

panel components.

(b) RWND, POWER, DOOR switches and

(10) Remove six flat head screws securing

ON/OFF circuit breaker are removed by unscrewing

harness and interface board assembly (33) to chassis

nut on front side of panel. When removing RWND

(1) and lift out assembly.

switch, first remove white plastic knob by pulling it

b. Replacement.

straight forward.

NOTE

unscrewing set screw in knob and then removing

The destination for all harness wiring is

nut.

hot stamped on wire markers. If in doubt,

(d) Elapsed time meter is removed by un-

use interconnecting wiring diagrams and

screwing two hex screws on rear of panel.

signal interconnection list (figs. FO-7,

b. Replacement.

FO-8 and FO-9). Use FO-10 for wire

(1) Place component in panel assembly.

routing and dressing details.

(2) Secure component to panel as follows:

(1) Solder harness wiring to all front panel

(a) LED socket is secured by nut on rear of

components.

panel.

(2) Solder harness wiring to phototransistor

(b) RWND, POWER, DOOR switches and

assemblies (A8A1, A8A2, A8A4), LED assemblies

ON/OFF circuit breaker are secured by nut on front

(A8A3, A8A5) and interlock switches (A8S1, A8S2).

side of panel. Push white plastic knob of RWND

(3) Position harness and interface board (33) in

onto switch shaft after securing nut.

chassis and secure in place with six flat head screws.

(4) Orient interface connector J2 (25) with wide

front side of panel. Replace knob on shaft and secure

key slot at top and secure connector to rear of

it with set screw.

chassis using four screws (26), washers (24) and nuts

(d) Elapsed time meter is secured with two

(23). Be sure that chassis ground lead to line filter

hex screws on rear side of panel.

FL1 is attached to connector screw.

(3) Solder leads to component.

(5) Secure line filter FL1 to chassis (para 3-26).

(4) Secure front panel assembly (3) to frame

(6) Secure connector A10P1 to the power

with six socket head screws (2).

supply by means of connector jackscrews. Alter-

nately tighten each screw one to two turns until

3-35. Motor and Tachometer Commutator

connector is seated.

Cleaning

(7) Install tape deck assembly A8 in chassis

(fig. 3-9)

(para 3-32).

a. Motor Commutator.

(8) Secure front panel assembly to chassis with

six socket-head screws.

(1) Remove capstan motor assembly (para

(9) Replace magnetic head assembly PU1 (para

3-29a).

3-31).

(2) Remove five screws (two pan head, three flat

(10) Replace capstan motor assembly B1 (para

head) securing front cap to motor housing.

3-29).

CAUTION

(11) Replace power amplifier assembly A9 (para

Hold down the capstan when removing

3-27).

from housing cap of motor assembly. This

(12) Replace circuit card assemblies Al through

will prevent armature from being pulled

A5 (para 3-24).

3-25