DOWNLOAD Sony HCD-H991AV / MHC-991AV / MHC-G99AV Service Manual ↓ Size: 871.8 KB | Pages: 60 in PDF or view online for FREE

— 13 —

Procedure:
1. Press  FUNCTION  button to select VIDEO.
2. Mode: record

4. Confirm playback the signal recorded in step 2 become adjustment

level as follows.
If these levels do not adjustment level, adjust the RV341 (L-CH)
and RV441 (R-CH) on the MD board to repeat steps 2 and 3.

Adjustment level: The playback output of 10 kHz level difference

against 315 Hz reference should be 

±

 0.5 dB.

Adjustment Location: MD board

main board
CN403 Pin 3 (L-CH)

Pin 1 (R-CH)

3. Mode: Playback

(Conductor Side)

3. Mode: Playback

4. Confirm playback the signal recorded in step 2 become adjustment

level as follows.
If these levels do not adjustment level, adjust the RV301 (L-CH)
and RV351 (R-CH) on the main board to repeat steps 2 and 3.

Adjustment level:

CN403 PB level: 47.2 to 53.0 mV (–24.3 to –23.3 dB)

Adjustment Location: MAIN board

Procedure:
1. Press  FUNCTION  button to select VIDEO.
2. Mode: record

(Component Side)

main board
CN403 Pin 3 (L-CH)

Pin 1 (R-CH)

}

Ω

Ω

— 14 —

µ

Note: As a front-end (FE1) is difficult to repair if faulty, replace it

with new one.

AM Tuned Level Adjustment
Note: FM Tuned Level adjustment should be performed after this

AM Tuned Level Adjustment.

Setting:
Band: AM or MW

µ

µ

Procedure:
1. Set the output of SSG so that the input level of the set becomes 55

dB.

2. Tune the set to 999 kHz or 1,050 kHz.
3. Adjust RV41 (except US, CND, E2, AR, AUS, TH model), RV42

(US, CND, E2, AR, AUS, TH model) to the point (moment) when
the TUNED  indicator will change from going off to going on.

Adjustment Location:  TCB board

FM Tuned Level Adjustment
Note: This adjustment should be performed after the AM Tuned Level
Adjustment.

Setting:
Band: FM

(Component Side)

(Component Side)

• Abbreviation

CND: Canadian model.
AR:

Argentine model.

AUS: Australian model.
TH:

Thailand model.

E2:

Without SW tuner model.

Procedure:
1. Supply a 25 dB 98 MHz signal from the ANTENNA terminal.
2. Tune the set to 98 MHz.
3. Adjust RV42 (except US, CND, E2, AR, AUS, TH model), RV41

(US, CND, E2, AR, AUS, TH model) to the point (moment) when
the TUNED indicator will change from going off to going on.

Ω

Ω

— 15 —

Setting:
Band: SW

Procedure:
1. Connect digital Voltmeter to diode D1 center lead and ground.
2. Adjust for a following value reading on digital voltmeter.

Adjustment

part

Setting:
Band: SW

Procedure:
Adjust for maximum reading on level meter.

Set frequency

• Repeat the procedures is each adjustment several times, and the

frequency coverage and tracking adjustment should be finally done
by the trimmer capacitors.

— Component Side —

• Abbreviation

EA: Saudi Arabia model.
MY: Malaysia model.
SP:

Singapore model.

HK: Hong Kong model.
IA:

Indonesian model.

E3:

With SW tuner model.

Set frequency

Reading on digital

voltmeter

SW

5.95 MHz

17.9 MHz

T2

CV2

1.2 

±

 0.1 V

8.5 

±

 0.2 V

SW

T1

CV1

7 MHz

17 MHz

Adjustment

part

— 16 —

Note:
1. CD Block is basically designed to operate without adjustment.

Therefore, check each item in order given.

2. Use YEDS-18 disc (3-702-101-01) unless otherwise indicated.
3. Use an oscilloscope with more than 10M

Ω

 impedance.

4. Clean the object lens by an applicator with neutral detergent when

the signal level is low than specified value with the following
checks.

5. Adjust the focus bias adjustment when optical block is replaced.

Procedure:
1. Connect oscilloscope to test point TP (RF). (Ground terminal : TP

(VC))

2. Turned Power switch on.
3. Put disc (YEDS-18) in and playback.
4. Adjust RV101 so that the waveform is clear.

(Clear RF signal waveform means that the shape “ ” can be clearly
distinguished at the center of the waveform.)

5. After adjustment, check the RF signal level.

• RF signal

VOLT/DIV: 200 mV
TIME/DIV: 500 nS

±

Procedure :
1. Connect oscilloscope to test point TP (FEO).
2. Connect between test point TP (FOK) and Ground by lead wire.
3. Turn Power switch on.
4. Put disc (YEDS-18) in and turned Power switch on again and

actuate the focus search. (actuate the focus search when disc table
is moving in and out.)

5. Check the oscilloscope waveform (S-curve) is symmetrical

between A and B. And confirm peak to peak level within 2.4 

±

 0.7

Vp-p.

6. After check, remove the lead wire connected in step 2.
Note: • Try to measure several times to make sure than the ratio of

A : B or B : A is more than 10 : 7.

• Take sweep time as long as possible and light up the

brightness to obtain best waveform.

Procedure :
1. Connect oscilloscope to test point TP (RF) on BD board.
2. Turned Power switch on.
3. Put disc (YEDS-18) in and playback.
4. Confirm that oscilloscope waveform is clear and check RF signal

level is correct or not.

Note: Clear RF signal waveform means that the shape “ ” can be

clearly distinguished at the center of the waveform.

±

±