JVC TV-13142 Service Manual page 19

1-4: CONFIRMATION OF VSR TORQUE
1. Install the Torque Gauge on the S Reel. Set to the
Picture Search (Rewind) mode. (Refer to Fig.1-4)
2. Then, confirm that it indicates 120~180gf•cm.
NOTE
Install the Torque Gauge on the reel disk firmly. Press the
REW button to turn the reel disk.
1-5: CONFIRMATION OF REEL BRAKE TORQUE
(S Reel Brake) (Refer to Fig. 1-4-B)
1. Once set to the Fast Forward mode then set to the Stop
mode. While, unplug the AC cord when the Pinch Roller
Block is on the position of Fig. 1-4-A.
2. Move the Idler Ass'y from the S Reel.
3. Install the Torque Gauge on the S Reel. Turn the
Torque Gauge clockwise.
4. Then, confirm that it indicates 60~100gf•cm.
(T Reel Brake) (Refer to Fig. 1-4-B)
1. Once set to the Fast Forward mode then set to the Stop
mode. While, unplug the AC cord when the Pinch Roller
Block is on the position of Fig. 1-4-A.
2. Move the Idler Ass'y from the T Reel.
3. Install the Torque Gauge on the T reel. Turn the Torque
Gauge counterclockwise.
4. Then, confirm that it indicates 45~70gf•cm.
The position at FF mode.
Stop at this position.
The position at
STOP mode.
Capstan DD Unit
Cassette Holder Ass'y
Torque Gauge
S Reel
MECHANICAL ADJUSTMENTS
Pinch Roller Block
Cassette
Opener
Fig. 1-4-A
Torque Gauge
T Reel
Fig. 1-4-B
NOTE
If the torque is out of the range, replace the following
parts.
Check item Replacement Part
1-4 Idler Ass'y/Clutch Ass'y
1-5 S Reel side: S Reel/Tension Band Ass'y/
Tension Arm Ass'y
T Reel side: T Reel/T Brake Spring/T Brake
Ass'y
2. CONFIRMATION AND ADJUSTMENT
OF TAPE RUNNING MECHANISM
Tape Running Mechanism is adjusted precisely at the
factory. Adjustment is not necessary as usual. When you
replace the parts of the tape running mechanism because
of long term usage or failure, the confirmation and
adjustment are necessary.
2-1: GUIDE ROLLER
1. Playback the VHS Alignment Tape (MHP).
2. Connect CH-1 of the oscilloscope to TP4001 (Envelope)
and CH-2 to TP1002 (SW Pulse).
3. Press and hold the Tracking-Auto button on the remote
control more than 2 seconds to set tracking to center.
4. Trigger with SW Pulse and observe the envelope. (Refer
to Fig. 2-1-A)
5. When observing the envelope, adjust the Roller Driver
(PTU94002) slightly until the envelope will be flat.
Even if you press the Tracking Button, adjust so that
flatness is not moved so much.
6. Adjust so that the A : B ratio is better than 3 : 2 as shown
in Fig. 2-1-B, even if you press the Tracking Button to
move the envelope (The envelope waveform will begin to
decrease when you press the Tracking Button).
7. Adjust the PG shifter during playback.
(Refer to the ELECTRICAL ADJUSTMENTS)
NOTE
After adjustment, confirm and adjust A/C head.
(Refer to item 2-2)
CH-1
Envelope
(TP4001)
CH-1
Track
CH-2
SW Pulse (TP1002)
Entrance
Max
A
A : B ≥ 3 : 2
TV-13142
TV-13142W
CH-2
Track
Fig. 2-1-A
Exit
Max
B
Fig. 2-1-B
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