Mechanical Adjustments; Electrical Adjustments - Sony HCD-VX77 Service Manual

SECTION 5

MECHANICAL ADJUSTMENTS

Precaution
1. Clean the following parts with a denatured alcohol-moistened
swab:
record/playback heads
erase head
capstan
2. Demagnetize the record/playback head with a head
demagnetizer.
3. Do not use a magnetized screwdriver for the adjustments.
4. After the adjustments, apply suitable locking compound to the
parts adjusted.
5. The adjustments should be performed with the rated power
supply voltage unless otherwise noted.
Torque Measurement
Mode
Torque meter
FWD CQ-102C
FWD
CQ-102C
back tension
REV CQ-102RC
REV
CQ-102RC
back tension
FF/REW CQ-201B
FWD tension CQ-403A
REV tension CQ-403R
pinch rollers
rubber belts
idlers
Meter reading
3.06 N • m to 6.96 N • m
31 to 71 g • cm
(0.43 – 0.98 oz • inch)
0.19 N • m to 0.58 N • m
2 to 6 g • cm
(0.02 – 0.08 oz • inch)
3.06 N • m to 6.96 N • m
31 to 71 g • cm
(0.43 – 0.98 oz • inch)
0.19 N • m to 0.58 N • m
2 to 6 g • cm
(0.02 – 0.08 oz • inch)
6.96 N • m to 14.02 N • m
71 to 143 g • cm
(0.98 – 1.99 oz • inch)
9.80 N • m
100 g or more
(3.53 oz or more)
9.80 N • m
100 g or more
(3.53 oz or more)
SECTION 6

ELECTRICAL ADJUSTMENTS

DECK SECTION
0 dB=0.775 V
1. Demagnetize the record/playback head with a head
demagnetizer.
2. Do not use a magnetized screwdriver for the adjustments.
3. After the adjustments, apply suitable locking compound to the
parts adjust.
4. The adjustments should be performed with the rated power
supply voltage unless otherwise noted.
5. The adjustments should be performed in the order given in this
service manual. (As a general rule, playback circuit adjustment
should be completed before performing recording circuit
adjustment.)
6. The adjustments should be performed for both L-CH and R-
CH.
7. Switches and controls should be set as follows unless otherwise
specified.
• Test Tape
Tape Signal
P-4-A100 10 kHz, –10 dB
WS-48B 3 kHz, 0 dB
P-4-L300 315 Hz, 0 dB
Record/Playback Head Azimuth Adjustment
DECK A DECK B
Note: Perform this adjustments for both decks
Procedure:
1. Mode: Playback
test tape
P-4-A100
(10 kHz, –10 dB)
set
Used for
Azimuth Adjustment
Tape Speed Adjustment
Level Adjustment
main board
CN301
Pin 3 (L-CH)
level meter
Pin 1 (R-CH)
+
–
main board
CN301
Pin 2 (GND)
17