Sony D-V55, Руководство по обслуживанию

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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 electro-
static 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 emis-
sion, 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. : 9-960-
027-11) 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
fl
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.
Method-2 (In the service mode or normal operation) :
Check the value of current flowing in the laser diode.
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)
Fig.1-1 Method to push S804
A C 2 2 1 1 3 9 7
year
version
month
A : less than 48 mA
current value
date
line No.
shift No.
Fig. 1-2 Digital Voltmeter Connecting Location
[MAIN BOARD] (SIDE B)
4 3
2
1
5
6
4 3
2
1
5
6
1
5
10 11
20
BC E
B
C
E
B
C
E
BCE
BCE
R532
C525
C526
R751
C518
D501
C516
R544
L506
R518
IC501
R520
R531
R522
R542
R514
C530
C507
R515
R513
R525
C522
C529
R512
R516
R543
C502
Q504
R510
Q506
Q502
R509
C509
R506
R554
R528
R507
R511
R521
R519
R517
R526
Q501
C519
R523
Q503
Q507
C508
R527
TP512
TP520
TP534
TP540
TP537
TP531
TP536
TP524
TP535(RFO)
TP522
(FE)
TP523 (TE)
TP508
(VC)
TP521
TP752
TP810
TP809
TP530
TP525
15
TP524
digital voltmeter
TP520
S804
3. Connect a digital voltmeter as shown in Fig. 1-2
4. Press the
fl
key.
5. Calculate the current value by the reading of the digital
voltmeter.
Reading of the digital voltmeter V ÷ 4.7
Ω
= current value (A)
(Example) Reading of the digital voltmeter of 0.2256 V :
0.2256 V ÷ 4.7
Ω
= 0.048 (A) = 48 mA
6. Check that the current value is within the following range.
+5
• 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.