DOWNLOAD Sony HCD-V919AV / MHC-V919AV Service Manual ↓ Size: 8.87 MB | Pages: 100 in PDF or view online for FREE

– 17 –

3. Mode:  Playback (FWD)

4. Repeat setps 1 to 3 in playback (REV) mode.
5. After the adjustments, apply suitable locking compound to the

pats adjusted.

Adjustment Location: Playback Head (Deck A).

 Record/Playback/Erase Head (Deck B).

Start the Tape Speed adjustment as below after setting to the test
mode.
In the test mode, the tape speed is high during pressing the

[HI-DUB]

 button.

Procedure:
1. Turn the power switch on.
2. Press the

p

button, 

[ENTER/NEXT]

 button and 

[DISC 3]

 button

simultaneously.
(The “VOLUME” on the fluorescent indicator tube will blink
while in the test mode.)
To exit from the test mode, press the

u

button.

Mode:  Playback

1. Insert the WS-48B into the deck B.
2. Press the

· button on the deck B.

3. Press the 

[HI-DUB]

 button in playback mode.

Then at HIGH speed mode.

4. Adjust RV1001 on the LEAF SW board do that frequency

counter reads 6,000 ± 180 Hz.

5. Press the 

[HI-DUB]

 button.

Then back to NORMAL speed mode.

6. Adjust RV1002 on the LEAF SW board so that frequency

counter reads 3,000 ± 90 Hz.

Adjustment Location:  LEAF SW board
Sample value of Wow and Flutter: 0.3% or less W.RMS (JIS)

(WS-48B)

Procedure:
Mode:  Playback

Deck A is RV311 (L-CH) and RV411 (R-CH), Deck B is RV301
(L-CH) and RV401 (R-CH) so that adjustment within adjustment
level as follows.
Adjustment Level:

CN301 PB level:  301.5 to 338.3 mV (–8.2 to  –7.2 dB) level
difference between the channels: within ± 0.5 dB

Adjustment Location:  AUDIO board

set

test tape
P-4-A100
(10 kHz, –10 dB)

(pin 

3

: R-CH)

oscilloscope

V

H

waveform of oscilloscope

in phase 45 

°

90 

°

135 

°

180 

°

good

wrong

(pin 

2

: GND)

(pin 

1

: L-CH)

MAIN board
CN301

Reverse

Foward

1

Remove the four claws

2

Window

+
–

set

test tape
WS-48B 
(3 kHz, 0 dB)

MAIN board
CN301 (Pin 

1

 : L-CH)

(Pin 

3

 : R-CH)

frequency counter

+
–

set

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

MAIN board
CN301 (Pin 

1

: L-CH)

(Pin 

3

: R-CH)

level meter

– 18 –

Procedure:
INTRODUCTION
When set to the test mode performed in 

Tape Speed Adjustment

,

when the tape is rewound after recording, the “REC memory mode”
which rewinds only the recorded portion and playback is set.
This  “REC memory mode” is convenient for performing this ad-
justment. During recording, the input signal FUNCTION will au-
tomatically switch to VIDEO.
(After recording, press the  – 

0 button without stopping will

return to the position where recording was started.)

1. Press 

[FUNCTION]

 button to select VIDEO. (This step is not

necessary if the above test mode has already been set.)

2. Insert a tape into deck B.
3. After press 

[    REC]

 button, press

P button, then recording

start.

4. Mode:  Record

5. Mode:  Playback

6. Confirm playback the signal recorded in step 3 become ad-

justable level as follows.
If these levels do not adjustable level, adjustment the RV341
(L-CH) and RV441 (R-CH) on the AUDIO board to repeat
steps 4 and 5.

Adjustable level: Playback output of 315 Hz to playback output

of 10 kHz: ± 1.0 dB

Adjustment Location:  AUDIO board

Procedure:
INTRODUCTION
When set to the test mode performed in 

Tape Speed Adjustment

,

when the tape is rewound after recording, the “REC memory mode”
which rewinds only the recorded portion and playback is set.
This  “REC memory mode” is convenient for performing this ad-
justment. During recording, the input signal FUNCTION will au-
tomatically switch to VIDEO.
(After recording, press the  – 

0 button without stopping will

return to the position where recording was started.)

1. Press 

[FUNCTION]

 button to select VIDEO. (This step is not

necessary if the above test mode has already been set.)

2. Insert a tape into deck B.
3. After press 

[    REC]

 button, press

P button, then recording

start.

4. Mode: Record

5. Mode:  Playback

6. Confirm playback the signal recorded in step 3 become ad-

justable level as follows.
If these levels do not adjustable level, adjustment the RV301
(L-CH) and RV351 (R-CH) on the MAIN board to repeat steps
4 and 5.

Adjustable level:
CN301 PB level:  47.2 to 53.0 mV (–24.3 to –23.3 dB)
Adjustment Location:  MAIN board

[MAIN  Board] (Component Side)

[AUDIO  Board]  (Component Side)

[LEAF  SW  Board]  (Component Side)

r

r

attenuator

+

–

+
–

+
–

set

MD/VIDEO (AUDIO) IN

1) 315 Hz
2) 10 kHz

50 mV (–23.8 dB)







600 

Ω

blank tape
CN-123

AF OSC

+
–

set

recorded
portion

MAIN board
CN301 (Pin 

1

: L-CH)

(Pin 

3

: R-CH)

level meter

set

MD/VIDEO (AUDIO) IN
315 Hz, 50 mV (–23.8 dB)

blank tape
CS-123

600 

Ω

attenuator

AF OSC

+
–

+
–

+
–

+
–

set

recorded
portion

MAIN board
CN301 (Pin 

1

: L-CH)

(Pin 

3

: R-CH)

level meter

RV301

L

REC LEVEL

RV351

R

IC301

CN301

1      3

RV401

RV301

RV341

RV311

RV411

IC602

CN601

L

R

R L





 





 

RV441

PB LEVEL

– DECK B –

REC BIAS

L

R





 

PB LEVEL

– DECK A –

TAPE SPEED

RV1002

RV1001

(NORMAL)  (HIGH)

CN1001





















– 19 –

1. CD block basically constructed to operate without adjustment.  There-

fore, check each item in order given.

2. Use YEDS-18 disc (Part No.: 3-702-101-01) unless otherwise indicated.
3. Use the oscilloscope with more than 10 M

Ω

 impedance.

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

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

Procedure:
1. Connect the oscilloscope to TP (FE) and TP (VC) on BD board.
2. Connect between test point TP (FOK) and GND by lead wire.
3. Turned 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. Confirm that the oscilloscope waveform (S-curve) is symmetri-

cal between A and B.  And confirm peak to peak level within
3.0 ± 1.0 Vp-p.

S-curve waveform

6. After check, remove the lead wire connected in step 2.

• Try to measure several times to make sure that 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 the oscilloscope to TP (RF) and TP (VC) on BD board.
2. Turned power switch on.
3. Put disc (YEDS-18) in and press the 

fl  button.

4. Confirm that the oscilloscope waveform is clear and check RF

signal level is correct or not.

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

within 3.0 ± 1.0 Vp-p

RF signal waveform

When observing the eye pattern, set the oscilloscope for AC range
and raise vertical sensitivity.

+
–

BD board

TP (FE)

TP (VC)

oscilloscope

A

B

symmetry

+
–

BD board

TP (RF)

TP (VC)

oscilloscope

(AC range)

VOLT/DIV: 200 mV
TIME/DIV: 500 ns
(with the 10: 1 probe 
in use)

level: 1.3        Vp-p

+0.25

–0.20

Procedure:
1. Short-circuit SL502 of the VIDEO board to GND.
2. Connect oscilloscope to test point TP (TE) on BD board.
3. Turned Power switch on. Press 

[FUNCTION]

 button to select

CD.

4. Put disc (YEDS-18) in to play the number five track.
5. Press the 

[PLAY MODE]

 button.

 (The tracking servo and the sledding servo are turned OFF.)

6. Check the level B of the oscilloscope’s waveform and the A

(DC voltage) of the center of the Traverse waveform.
Confirm the following:

Traverse waveform

7. Press the 

[PLAY MODE]

 button. (The tracking servo and sled-

ding servo are turned ON.) Confirm the C (DC voltage) is al-
most equal to the A (DC voltage) is step 6.

Traverse waveform

8. Desolder the short-land (SL502) short-circuited at step 1.

A    

×

 100 = less than ± 22 (%)

B

level: 1.3 ± 0.6 Vp-p

+
–

BD board

TP (TE)
TP (VC)

oscilloscope

A (DC 

voltage)

B

0 V

Center of the waveform

C (DC 

voltage)

0 V

Tracking servo

Sled servo

OFF

Tracking servo

Sled servo

ON

– 20 –

[BD  Board] (Side A)

CN102

CN101

IC103

IC101

TP

(FOK)

TP

(TE)

TP

(FE)

TP (RF)
TP (VC)