HCD-H991AV, MHC-991AV, MHC-G99AV - Sony Audio Service Manual (repair manual). Page 11

— 11 —

Precaution
1. Clean the following parts with a denatured alcohol-moistened

swab:

record/playback heads

pinch rollers

erase head

rubber belts

capstan

idlers

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.

1. Demagnetize the record/playback head with a head damagnetizer.
2. Do not use a magnetized screwdriver for the adjustments.
3. After the adjustments, apply suitable locking compound to the

parts adjusted.

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.

DOLBY NR switch: OFF

2 to 6 g • cm

(0.02 - 0.08 oz • inch)

61 to 143 g • cm

(0.85 - 1.99 oz • inch)

100 g or more

(3.53 oz or more)

100 g or more

(3.53 oz or more)

Torque

Torque meter

Meter reading

FWD

FWD
back tension

REV

REV
back tension

FF/REW

FWD tension

REV tension

CQ-102C

CQ-102C

CQ-102RC

CQ-102RC

CQ-201B

CQ-403A

CQ-403R

36 to 61 g • cm

(0.5 - 0.84 oz • inch)

2 to 6 g • cm

(0.02 - 0.08 oz • inch)

36 to 61 g • cm

(0.5 - 0.84 oz • inch)

Note: Perform this adjustments for both decks.

Procedure:
1. Mode : Playback

main board
CN403
Pin 3 (L-CH)
Pin 1 (R-CH)

main board
CN403
Pin  2 (GND)

Signal

Used for

10 kHz, –10 dB

3 kHz, 0 dB

315 Hz, 0 dB

Azimuth Adjustment

Tape Speed Adjustment

Level Adjustment

Tape

P-4-A100

WS-48B

P-4-L300