DOWNLOAD Sony MHC-VX333 (serv.man2) Service Manual ↓ Size: 12.12 MB | Pages: 70 in PDF or view online for FREE

17

Procedure:
1.

Supply a 98 MHz signal at 28 dB from the ANTENNA terminal.

2.

Tune the set to 98 MHz.

3.

Adjust RV101 to the point (moment) when the TUNED
indicator will change from going off to going on.

Adjustment Location: MAIN board

Procedure:
1.

Supply a 98 MHz signal at 60 dB from the ANTENNA terminal.

2.

Tune the set to 98 MHz.

3.

Measure voltage between pin 21 and pin 23 of IC 101.  Adjust
T101 ubtil the voltage becomes 0 V.

Adjustment Location: MAIN board

FM RF Signalgenerator

75 

Ω

 coaxial

Carrier frequency : 98 MHz
Modulation           : AUDIO 1 kHz, 75 kHz
                              deviation (100%)
Output level          : 28 dB  (at 75 

Ω

 open)

FM ANTENNA terminal
(TM101)

set

FM RF Signalgenerator

75 

Ω

 coaxial

Carrier frequency : 98 MHz
Modulation           : AUDIO 1 kHz, 75 kHz
                              deviation (100%)
Output level          : 60 dB  (at 75 

Ω

 open)

FM ANTENNA terminal
(TM101)

set

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.

Procedure :
1. Connect oscilloscope to TP (FE0).
2. Connect between TP (FEI) and TP (VC) by lead wire.
3. Connect between TP (AGCCON) and TP (D GND) by lead wire.
4. Turn Power switch on.
5. Load a disc (YEDS-18) and actuate the focus search. (In

consequence of open and close the disc tray, actuate the focus
search)

6. Confirm that the oscilloscope waveform (S-curve) is

symmetrical between A and B. And confirm peak to peak level
within 4 

±1 Vp-p.

7. After check, remove the lead wire connected in step 2 and 3.

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 TP (RF).
2. Connect between TP (AGCCON) and TP (D GND) by lead wire.
3. Turned Power switch on.
4. Load a disc (YEDS-18) and playback.
5. Confirm that oscilloscope waveform is clear and check RF signal

level is correct or not.

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

±

T101

IC101

RV101

T101:NULL

RV101:FM TUNED LEVEL

18

Note : Clear RF signal waveform means that the shape “ 

◊ ” can be clearly

distinguished at the center of the waveform.

Procedure :
1. Connect oscilloscope to TP (TE0) and TP (VC).
2. Turned Power switch on.
3. Load a disc (YEDS-18) and playback the number five track.
4. Press the  gG  button. (Becomes the 1 track jump mode.)
5. Confirm that the level B and A (DC voltage) on the oscilloscope

waveform.

6. After check, remove the lead wire connected in step 1.

±

±

Specified level: –– 

× 100=less than ±22%

B

A

[BD BOARD] (Conductor Side)

Procedure:
1. Connect the frequency counter to check point of the VIDEO

board.

2. Turned power switch on.
3. Press the  CD  button to select the CD.
4. Adjust CT503 on the VIDEO board so that the frequency counter

reading 27.0 MHz 

± 80 Hz at stop status.

[VIDEO CD BOARD] (Component Side)

19

Note on Schematic Diagram:
• All capacitors are in 

µ

F unless otherwise noted.  p: pF. 50

WV or less are not indicated except for electrolytics and
tantalums.

• All resistors are in 

Ω

 and 

1

/

4

 

W or less unless otherwise

specified.

•

¢

: internal component.

•

C

: panel designation.

• X

: parts extracted from the component side.

• b

: Pattern from the side which enables seeing.

• Indication of transistor.

•

A

: B+ Line.

•

B

: B– Line.

•

H

: adjustment for repair.

• Voltages and waveforms are dc with respect to ground

under no-signal (detuned) conditions.

• Voltages are taken with a VOM (Input impedance 10 M

Ω

).

Voltage variations may be noted due to normal produc-
tion tolerances.
no mark : FM
(

) : CD

[

] : TAPE

• Waveforms are taken with a oscilloscope.

Voltage variations may be noted due to normal produc-
tion tolerances.

• Circled numbers refer to waveforms.

• Signal path.

F

: FM

f

: AM

E

: PB (DECK A)

d

: PB (DECK B)

G

: REC (DECK B)

J

: CD

c

: digital out

C

B

These are omitted.

E

Q

B

These are omitted.

C

E

Q

• Abbreviation

MY

: Malaysia model.

SP

: Singapore model.

TH

: Thai model.

EA

: Saudi Arabia model.

JE

: Tourist model.

IA

: Indonesian model.

TW

: Taiwan model.

Note: The components identified by mark 

0

 or dotted line

with mark 

0

 are critical for safety.

Replace only with part number specified.

• Abbreviation

MY

: Malaysia model.

SP

: Singapore model.

TH

: Thai model.

EA

: Saudi Arabia model.

JE

: Tourist model.

IA

: Indonesian model.

TW

: Taiwan model.

TRANS board

MOTOR board

ADDRESS SENSOR board

DRIVER board

VIDEO CD board

SENSOR board

BD board

VIDEO OUT board

SUB TRANS board

MAIN board

POWER AMP board

PANEL board

KEY board

Caution:
Pattern face side:

Parts on the pattern face side seen from

(Side B)

the pattern face are indicated.

Parts face side:

Parts on the parts face side seen from

(Side A)

the parts face are indicated.

20