SECTION 1
SERVICING NOTES
5. Calculate the current value by the reading of the digital voltmeter.
NOTES ON HANDLING THE OPTICAL PICK-UP BLOCK OR
Reading of the tester (V) � 4.7 ( W ) = current value (A)
BASE UNIT
(Example) Reading of the digital voltmeter of 0.2256 V :
The laser diode in the optical pick-up block may suffer electrostatic0.2256 V � 4.7 W = 0.048 (A) = 48 mA
6. Check that the current value is within the following range.
breakdown because of the potential difference generated by the charged
+5
electrostatic load, etc. on clothing and the human body. During repairY Current value of the label,-11 mA(25°C)
pay attention to electrostatic breakdown and also use the procedure inVariation by temperature : 0.4mA°C /
the printed matter which is included in the repair parts.Current increases with temperature increased.
The flexible board is easily damaged and should be handled with care.Current decreases with temperature decreased.
If the current is more than the range above, there is a trouble in the
NOTES ON LASER DIODE EMISSION CHECKautomatic power control circuit or the laser diode is in deterioration.
The laser beam on this model is concentrated so as to be focused on theIf less than the range, a trouble exists in the automatic power control
disc reflective surface by the objective lens in the optical pick-up block.circuit or the optical pick-up.
Therefore, when checking the laser diode emission, observe from more
than 30cm away from the objective lens.[MAIN BOARD] (Side B)
Before Replacing the Optical pick-up Block
Please be sure to check thoroughly the parameters as per the OOptical
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.
Y FOK output : IC501 !a pin
When checking FOK, remove the lead wire to disc motor.
Y S curve P-to-P value : 0.9 � 1.5Vp-p IC501 #� pin. (Connect pin !a
of IC501 (TP880) and 3 of IC501 (GND) with a jumper wire).
When checking S curve P-to-P value, remove the lead wire to disc
motor.
Y Adjusted part for focus gain adjustment : RV503
Y RF signal P-to-P value : 0.8 � 1.2Vp-p
Y Traverse signal P-to-P value : 1.0 � 2.4Vp-p
Y The repairing grating holder is impossible.
Y Adjusted part for tracking gain adjustment : RV502
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 S801
(push switch type).
The following two checking methods for the laser diode are operable.digital voltmeter
Method-1 (In the service mode or normal operation) :
TP506
Emission of the laser diode is visually checked.
TP547
1. Open the upper lid.
2. Push the S801 as shown in Fig. 1-1 .
3. Check the object lens for confirming normal emission of the laser
R806
diode. If not emitting, there is a trouble in the automatic power3630 2519
control circuit or the optical pick-up. During normal operation, the TP501
3718
laser diode is turned ON about 2.5 seconds for focus searching.80C806
4015 IC801
TP821
X801
4510
505
P822
7
541
S801
55 60 65 70 72
TP511
C879TP502
C516
TP512
TP523
TP503
TP507TP816 C549R809R510
Fig. 1-1 Method to push S801(TEST)Q501
L502
TP508
Method-2 (In the service mode or normal operation) :TP506R506 TP532
R507
Check the value of current flowing in the laser diode. TP547
R505
1. Remove the upper panel.TP534TP555R509
2. Read the current printed on the rear side of the optical pick-up.
TP505
(Print on the rear side of the optical pick-up)TP518
AC2211397
Fig. 1-2 Digital Voltmeter Connecting Location
current valueyear
A : less than 48 mAmonth
date
shift No.
line No.
version
3. Connect a digital voltmeter as shown in Fig. 1-2
4. Press the ^ key.
� 3 � |
ACEC
