DOWNLOAD Sony HCD-H551 / MHC-551 / MHC-G55 Service Manual ↓ Size: 742.87 KB | Pages: 50 in PDF or view online for FREE

— 9 —

.

*

Note: It  will be easy to remove if you push

lightly from the hole of the JOG board
with some screwdrivers or etc.

 

3

Nut

1

Knob (VOL) 

*

 Note

2

Knob (JOG) 

*

 Note

4

Nut

0

Three claws

!¡

Claw

9

Two claws

!£

Panel board

8

Six screws
(+BVTP2.6X8)

6

HP board

5

Two  screws
(+BVTP2.6X8)

!™

JOG board

7

Six screws
(+BVTP2.6X8)

Screw driver

— 10 —

1

Remove the connectors
(Main board: CN201)
(Loading board: CN291)

4

CD block
(CD mechanism deck
and CD chassis)

3

Two screws
(+BVTP3X8)

2

PC board holder

CN291

CN201

3

Remove the CD mechanism
deck direction of arrow.

1

Two screws
(+BVTP3X8)

2

Two claws

— 11 —

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

FWD

REV

REV
back tension

FF/REW

FWD tension

CQ-102C

CQ-102C

CQ-102RC

CQ-102RC

CQ-201B

CQ-403A

CQ-403R

2 to 6 g • cm

(0.02 - 0.08 oz • inch)

36 to 61 g • cm

(0.5 - 0.84 oz • inch)

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)

FWD

back tension

REV tension

Torque

Torque meter

Meter reading

36 to 61 g • cm

(0.5 - 0.84 oz • inch)

Signal

Tape

Used for

P-4-A100

WS-48B

P-4-L300

10 kHz, –10 dB

3 kHz, 0 dB

315 Hz, 0 dB

Azimuth Adjustment

Tape Speed Adjustment

Level Adjustment

 Perform this adjustments for both decks.

Procedure:
1. Mode : Playback

test tape
P-4-A100
(10kHz, –10dB)

main board
CN403
Pin 

3

 (L-CH)

Pin 

1

 (R-CH)

set

main board
CN403
Pin 

2

 (GND)

level meter

+

— 12 —

2. Turn the adjustment screw and check output peaks. If the peaks

do not match for L-CH and R-CH, turn the adjustment screw so
that outputs match within 1 dB of peak.

3. Mode: Playback

main board
CN403
Pin 

3

 (L-CH)

Pin 

2

 (GND)

set

L

R

test tape
P-4-A100
(10kHz, –10dB)

oscilloscope

Waveform of oscilloscope

in phase

45˚

90˚

135˚

180˚

wrong

good

Pin 

1

 (R-CH)

 Start the Tape Speed adjustment as below after setting the

test mode.
The tape speed can be changed with the  HIGH SPEED
DUBBING   button during the test mode.

Method :
1. Turn the power switch on.
2. Press the  DISPLAY/DEMO  button,  MENU 1  button and

TUNER/BAND   button simultaneously.

Procedure :
Mode: Playback

frequency counter

+
–

main board
CN403 Pin 

3

 (L-CH)

Pin 

1

 (R-CH)

set

test tape WS-48B
(3kHz, 0dB)

1. Insert the WS-48B into the deck A to playback.
2. Press the  HIGH SPEED DUBBING  button. Then at HIGH

SPEED mode.

3. Adjust the RV652 on the MD board so that the frequency

counter reading becomes 6,000 ± 30 Hz.

4. Press the HIGH SPEED DUBBING button again to be set the

NORMAL SPEED mode.

5. Set to the playback mode.
6. Adjust the RV651 on the MD board so that the frequency

counter reading becomes 3,000 ± 15 Hz.

Frequency difference between deck A and deck B the beginning
of the tape should be within ± 1.5%.

Adjustment Location: MD board

Mode: Playback

set

main board
CN403 Pin 

3

 (L-CH)

Pin 

1

 (R-CH)

level meter

Deck A is RV311 (L-CH) and RV411 (R-CH), deck B is RV301
(L-CH) and RV401 (R-CH)
so that adjustment within the following adjustment level.

CN403 playback level: 301.5 to 338.3 mV (–8.2 to –7.2 dB)
level difference between the channels: within ± 0.5 dB

Adjustment Location: MD board

test tape P-4-L300
(315Hz, 0dB)

L-CH
peak

output
level

within
1dB

within 1dB

R-CH
peak

screw
position

L-CH
peak

screw
position

R-CH
peak

4. After the adjustments, apply suitable locking compound to the

parts adjusted.

Adjustment Location: Playback Head (Deck A)

  Record/Playback/Erase Head (Deck B)

Adjustment screw

FWD side

REV side