SONY DV55
Service Manual

SECTION 1 SERVICING NOTE
NOTES ON HANDLING THE OPTICAL PICK-UP BLOCK OR BASE UNIT
The laser diode in the optical pick-up block may suffer electrostatic breakdown because of the potential difference generated by the charged electrostatic load, etc. on clothing and the human body. During repair, pay attention to electrostatic breakdown and also use the procedure in the printed matter which is included in the repair parts. The flexible board is easily damaged and should be handled with care. NOTES ON LASER DIODE EMISSION CHECK The laser beam on this model is concentrated so as to be focused on the disc reflective surface by the objective lens in the optical pick-up block. Therefore, when checking the laser diode emission, observe from more than 30cm away from the objective lens. Before Replacing the Optical pick-up Block Please be sure to check thoroughly the parameters as per the �Optical pick-up Block Checking Procedure� (Part No. : 9-960027-11) issued separately before replacing the optical Pick-up block. Note and specifications required to check are given below. � FOK output : IC601 ((£ pin (FOK). When checking FOK, remove the lead wire to disc motor. � S curve P-to-P value : 1.2 � 2Vp-p IC501 !§ pin. When checking S curve P-to-P value, remove the lead wire to disc motor. � RF signal P-to-P value : 0.5 � 0.9Vp-p � Traverse signal P-to-P value : 1.2 � 2.0Vp-p � The repairing grating holder is impossible. Laser Diode Checking Methods During normal operation of the equipment, emission of the laser diode is prohibited unless the upper panel is closed while turning ON the S804 (push switch type). The following two checking methods for the laser diode are operable. Method-1 (In the service mode or normal operation) : Emission of the laser diode is visually checked. 1. Open the upper lid. 2. Push the S804 as shown in Fig. 1-1. 3. Press the � key. 4. Check the object lens for confirming normal emission of the laser diode. If not emitting, there is a trouble in the automatic power control circuit or the optical pick-up. During normal operation, the laser diode is turned ON about 2.5 seconds for focus searching.
TP810

AC2211397 current value A : less than 48 mA year month date shift No. line No. version

3. Connect a digital voltmeter as shown in Fig. 1-2 4. Press the � key. 5. Calculate the current value by the reading of the digital voltmeter. Reading of the digital voltmeter V ÷ 4.7 � = current value (A) (Example) Reading of the digital voltmeter of 0.2256 V : 0.2256 V ÷ 4.7 � = 0.048 (A) = 48 mA 6. Check that the current value+5 within the following range. is � Current value of the label -11 mA(25�C) Variation by temperature : 0.4mA / �C Current increases with temperature increased. Current decreases with temperature decreased. If the current is more than the range above, there is a trouble in the automatic power control circuit or the laser diode is in deterioration. If less than the range, a trouble exists in the automatic power control circuit or the optical pick-up.
Q506

[MAIN BOARD] (SIDE B)
R543 L506 R542 C529 R518 R525 C519 R523 R517 R513 R510 R511 C509 TP521

R522 R528

IC501
R507 TP512 R506

digital voltmeter TP524 TP520

C516

R516

R544

C526

R512

TP522 TP523 (FE) (TE)

Fig.1-1 Method to push S804
E C B TP540 R554
E C B

C530

BCE

C508

Fig. 1-2 Digital Voltmeter Connecting Location

�3�

Q501

R531

R532

1. Remove the upper panel. 2. Read the current printed on the rear side of the optical pick-up. (Print on the rear side of the optical pick-up)

BC E

C525 TP534

D501

Method-2 (In the service mode or normal operation) : Check the value of current flowing in the laser diode.

TP537 TP530 R527 Q503

TP535(RFO) TP524

TP520

C507

C502

R509

R514

R520

Q504

Q507

TP525

BCE

R521 C518

Q502

S804

R519

6 5 4

16 25 34 R526

1 2 3 R515

R751

TP752 TP508 (VC)
11 15 20 5 1 10

TP809 C522 TP531 TP536