Periodically
the
cartridge
center
post should
be
cleaned.
Gummy
deposits
on
the
post,
in
effect,
increase tape tension
by
not allowing the
tape
hub
to turn
freely.
Equally important to free
movement
of the
hub
is
the
teflon
washer. Periodically check the pressure
pads
to see
that
they
are lined
up
squarely with the tape.
The
most
frequent cause of
distortion
of the tape path
in
the
cartridge
is
a loose corner post.
The
post should always
be
glued
down
so
that
there
is
1/4 inch
between
the shoulder of the post
and
the
shell.
If
the post
is
high the tape will not
run
straight
across the heads. A loose
post frequently causes muffled-sounding audio
when
the
cartridge
unit
starts.
5-27.
MECHANICAL
PARTS
REPLACEMENT
WAIIUIII
NIG I
BE
CERTAIN
THE
LARGE
ELECTROLYTIC
CAPACITORS
ON
THE
POWER
SUPPLY
BOARD
AND
THE
MOTOR
CAPACITORS
ON
THE
CHASSIS
ARE
FULLY
DISCHARGED
BEFORE
ATTEMPTING
MAINTENANCE
INSIDE
THE
UNIT.
5-28.
MOTOR
REPLACEMENT
I NIO'I'IE
CARE
MUST
BE
EXERCISED
IN
HANDLING
AND
STORING
MOTORS
TO
AVOID
DAMAGING
THE
BEARINGS.
STORE
SPARE
MOTORS
IN
THE
ORIGINAL
PACKAGING.
DO
NOT
HANDLE
THE
MOTOR
BY
THE
SHAFT,
BUT
BY
THE
CASE.
DO
NOT
SUBJECT
THE
MOTOR
TO
SHARP
BLOWS
OR
ROUGH
HANDLING.
Refer to
Drawing
D906-3122.
Disconnect the
ac
power
cord
and
remove
the top
and
bottom
covers.
Place the
unit
on
its
left
side.
Disconnect the motor leads
connector
from
the
Power
Supply Printed
Circuit
Board.
Grasp
the motor
in
one
hand, unscrew the
two
10-32 mounting screws
on
the top of the deck,
and
remove
the motor.
Remove
the motor mounting bracket
from
the motor
and
reinstall
the bracket
on
the replacement motor.
Install
the replace-
ment
motor
and
reconnect the
motor
leads to the
Power
Supply
printed
circuit
board. Perform the
deck
adjustments described in paragraph 5-35.
When
these adjustments are complete, reconnect
and
turn
on
the
ac
power.
The
motor
shaft
shou1d
rotate
counter-clockwise.
Finally,
test
operate the
unit
with a
cartridge
in both
normal
and
fast
forward
(if
so
equipped).
29
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