4
D-NE900
SECTION 1
SERVICING NOTE
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: IC601
yg
pin
When checking FOK, remove the lead wire to disc motor.
• RF signal P-to-P value: 0.45 to 0.65 Vp-p
NOTES ON HANDLING THE OPTICAL PICK-UP
BLOCK OR BASE UNIT
Fig. 1 Method to push the S812
S812
IC601 FOK
output
yg
p
MAIN BOARD (SIDE B)
IC601
LASER DIODE AND FOCUS SEARCH OPERATION
CHECK
During normal operation of the equipment, emission of the laser
diode is prohibited unless the upper lid is closed while turning ON
the S812. (push switch type)
The following checking method for the laser diode is operable.
• Method:
Emission of the laser diode is visually checked.
1. Remove the upper lid. (Please refer to disassembly.)
2. With a disc not set, turn on the S812 with a screwdriver having a
thin tip as shown in Fig.1.
3. Press the
u
button.
4. Observing the objective lens, check that the laser diode emits
light.
When the laser diode does not emit light, automatic power control
circuit or optical pickup is faulty.
In this operation, the objective lens will move up and down 4
times along with inward motion for the focus search.
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