Sharp GF-777H - Page 10

MECHANICAL ADJUSTMENT
Pinch Roller Pressure Check
1) Set the unit in play mode.
2) Push a tension gauge (0 to 500 g) into the pinch roller lever
to make the pinch roller off the capstan, and release the
gauge applied force gently so that the pinch roller sets back
to the capstan (the pinch roller again rotates).
At the time, the tension gauge reading must be 300 to
380 g.
3) If the step 2) is unsatisfied, bend the pinch roller pressure
spring properly, or renew it.
=
TORQUE
CHECK
AT
PLAY,
FAST
FORWARD
AND
REWIND
MODES
Put
a
torque
meter
cassette
in
the
cassette
compartment
of
the
set,
and
see
that
the
measured
torque
in
each
mode
is
normal
as follows:
Mode
Torque
meter
cassette
|
Measured
torque
Playback
TW-2111
35
~
60
gram-cm
Fast-forward
TW-2231
90
~
135
gram-cm
TW-2231
90
~
135
gram-cm
Tw-2231
TwW-2111
Figure
10-2
=
GAP
CHECK
OF
PINCH
ROLLER
LEVER
©
Place the set in play mode, and see that the pinch roller lever
moves to create the gaps (A), (B) and © as shown in Fig. 10-3.
Play Release Lever
Pinch Roller Lever
:
Figure
10-3
Tape
Speed
Adjustment
1) Reproduce a test tape (TEAC, MTT—111, 3 kHz-
prerecorded) — the playback must be at the middle of the
tape but not at either the beginning or the end.
2) Connect a wow/flutter meter, across a 100K ohm resistor,
to the line output socket.
3) Adjust the semi-variable resistor, using a plastic screwdriver
via the hole at the motor unit bottom, so that the playback
frequency will be 2,985 to 3,015 Hz (Deck 1) and 2,970 to
3,000 Hz (Deck 2).
Note:
The motor pulley, flywheel drive belt, flywheel, take-up
pulley, take-up idler and take-up turntable, etc. must be free
of any contamination.
Figure 10-4
~10—