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SECTION 2
SERVICE 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 30 cm away from the objective lens.
Before Replacing the Optical Pick-Up Block
Please be sure to check thoroughly the parameters as par the “Optical
Pick-Up Block Checking Procedures” (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: IC501!™ pin
When checking FOK, remove the lead wire to disk motor.
• S curve P-to-P value: 1.0-2.8Vp-p IC501#¡pin
When checking S curve P-to-P value, remove the lead wire to
disc motor.
• RF signal P-to-P value: 0.8-1.2Vp-p
• Traverse signal P-to-P value: 1.2Vp-p
• The repairing grating holder is impossible.
Precautions for Checking Emission of Laser Diode
Laser light of the equipment is focused by the object lens in the
optical pick-up so that the light focuses on the reflection surface of
the disc. Therefore, be sure to keep your eyes more then 30 cm
apart from the object lens when you check the emission of laser
diode.
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.
• Method (In the service mode or normal operation):
Emission of the laser diode is visually checked.
1. Open the upper lid.
2. Push the S801 as shown in Fig. 1.
3. 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.
Fug. 1 Method to push the S801
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