TM
11-5835-243-34/EE641-AA-MMI-010/E154
MTT/TO
31S34-110-1
(1) Remove four pan head screws securing rear
a. Motor Brush Assembly Removal.
cap to motor housing.
(1) Remove motor from tape transport (pan
(2) Hold down shaft located in center of rear cap
3-29) and place on a flat, solid work surface.
and carefully remove rear cap.
NOTE
(3) Remove two screws securing brush
Note carefully the routing and dressing of
assembly to motor housing.
brush assembly leads before unsoldering.
(4) Carefully lift out brush assembly.
Make certain that the new leads are in-
(5) Clean tachometer commutator (para 3-35).
stalled correctly.
d. Tachometer Brush Assembly Replacement.
(2) Locate two orange and two green wires from
CAUTION
each brush assembly and carefully unsolder them
Do not remove armature assembly from
from motor terminals (E1, E2, E44, and ES, fig.
stator when replacing brushes. If ar-
mature is removed from stator, entire
CAUTION
motor must be replaced.
Hold down capstan when removing the
(1) Place brush assembly into motor housing
front housing cap. This will prevent the
and carefully slide brushes onto commutator.
armature from being pulled out from the
(2) Secure brush assembly to motor housing
stator. If armature is accidentally
with two screws. Place a drop of sealant on screw
removed from stator, entire motor
threads before installing.
assembly must be replaced.
(3) Replace and secure rear housing cap to
(3) Remove five screws (two pan head, three flat
motor housing with four head screws. Place a drop
head) securing front cap to motor housing.
of sealant on screw threads before installing.
(4) Hold down capstan and front cap.
(4) Assemble brush assembly leads into the
(5) Remove two screws securing brush
harness following the routing of original leads.
assembly to motor housing.
(6) Form a small servce loop and solder each
(6) Carefully lift out brush assembly.
wire to correct motor terminal (fig. 3-9).
(7) Clean motor commutator (para 3-35).
(6) Install motor into tape transport (para
(8) Install new motor brush assembly before
removing tachometer brush assembly.
3-31. Magnetic Head Assembly PU1
b. Motor Brush Assembly Replacement.
(16, fig. 3-7)
CAUTION
a. Removal.
Do not remove armature assembly from
(1) Remove circuit cards A1 through A5 (para
stator when replacing brushes. If ar-
mature is removed from stator, entire
(2) Remove power amplifier assembly A9 (para
motor must be replaced.
(1) Place brush assembly into motor housing
(3) Remove two cable clamps holding head
and carefully slide brushes onto commutator.
assembly cables to tape deck.
(2) Secure brush to motor housing with two
CAUTION
screws. Place a drop of sealant on screw threads
Alternately turn jackscrews one to two
before installing.
turns each until plug separates com-
(3) Replace and secure front housing cap with
pletely from jack.
five screws (two pan head, three flat head). Place a
drop of sealant on screw threads before installing.
(4) Remove connectors PU1P1 and PU1P2
(4) Remove tachometer brush assembly (para
from interface board jacks A10A1J1 and A10A1J2
c., below).
by unscrewing two jackscrews on each connector.
c. Tachometer Brush Assembly Removal.
(5) Remove two socket head recessed screws
(15) and flat washers holding head assembly to tape
CAUTION
deck.
Hold down shaft which is located in the
(6) Lift out head assembly (16).
center of the cap when removing the rear
b. Replacement. The head assembly is aligned
housing cap. This will prevent armature
using a head alignment fixture, P/N T494-2311 and
from being pulled out from stator. If
a head stack gage, P/N 460-1000-143. Shims are
armature is accidentally removed from
placed between the head base and tape deck
stator, entire motor must be replaced.
nameplate to properly position the head assembly.
3-21
