VC-MH75 (serv.man6). Adjustment, replacement and assembly of mechanical units - Sharp VCR Service Manual (repair manual). Page 7

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14
VC-MH75HM
Figure 4-11.
4-12 CHECKING AND ADJUSTMENT OF
TENSION POLE POSITION
4-10 CHECKING THE VIDEO SEARCH REWIND
BACK TENSION
• Remove the cassette housing control assembly.
• After short-circuiting between TP803 and TP802
provided at main PWB, plug in the power cord.
• Checking
1. After pressing the play button, press the rewind button,
and set the video search rewind mode.
2. Place the torque gauge on the take-up reel disk, and turn
it counterclockwise very slowly (one rotation every 2 to
3 seconds) and check that the torque is within the set
value 3.7 ± 1.5mN
m (38 ± 15gf
cm).
Pinch roller
Tension gauge
900 - 1,200gf
Capstan shaft
Tension gauge adapter
Figure 4-10.
Torque gauge
Take-up reel disk
Notes:
Set the torque gauge securely on the take-up reel disk.
If it is not secure, the measurement will be incorrect.
4-11 CHECKING THE PINCH ROLLER
PRESSURE
CCW
Figure 4-12.
500g
Weight to prevent
float (500g)
(E-180)
Remove the cassette housing control assembly.
After short-circuiting between TP803 and TP802 pro-
vided at main PWB, plug in the power cord.
Checking
Press the play button to set the playback mode.
1. Detach the pinch roller from the capstan shaft.
Do not separate excessively. Or the pinch lever and
pinch double action lever may disengage.
2. Engage the tension gauge adapter with the pinch roller
shaft, and pull in the arrow direction.
3. Gradually return the pinch roller, and measure the pull-
ing force when the pinch roller contacts the capstan
shaft.
4. Make sure that the measured value is within setting
change to 9.8 ± 2N (1.0 ± 0.2kgf).
Checking can be perform with or without
cassette housing control.
Remove the cassette housing control assembly.
After short-circuiting between TP803 and TP802 pro-
vided at main PWB, plug in the power cord.
Setting (without cassette housing control)
1. Turn off the power switch.
2. Open the cassette tape (E-180), and fix with tape.
3. Set the cassette tape in loading state.
4. Put the weight (500g) on the cassette tape.
5. Turn on the power switch.
6. Make the adjustment with the beginning of a E-180 tape.
Checking can be perform with or without
cassette housing control.
• Setting (with cassette housing control)
1. Insert cassette tape (E-180).
2. Make the adjustment with the beginning of a E-180
tape.
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