Sharp XL-35 Service Manual page 32

XL-35/35C
• Laser failure.
Is +6.2V applied to the emitter of Q804 ?
Yes
Is +5V applied to the collector of Q804 ?
Yes
Is +5V applied to the pin 3 (VCC) of IC802 ?
Yes
Is 0V applied to the pin 40 of IC801 ?
Yes
Is approx. 2V applied to the collector of Q801.
Yes
Check CNW802/CNS802. If it is normal, the optical pickup is
faulty.
• Focus failure.
Does the optical pickup move up and down when the disc is
removed?
Yes
Is the following waveform output at the pin 32 (FE) of IC801
when the disc is set? (See Fig.29-1)
Yes
IC802 is faulty.
Check the PWB pattern between pin 5 of CNS605 and emitter of
No
Q804.
Check the peripheral parts of IC804 and Q804.
No
Check the PWB pattern between collector of Q804 and pin 3 of
No
IC802.
Does the laser come on when pattern cut between pin 24 of IC802
No
and pin 40 of IC801 ?
No
Check the PWB pattern between IC701 and IC801 (MCLK/MLD/
MDATA/BL)
Check the peripheral parts of IC802 and Q801. If it is normal, the
No
optical pickup is faulty.
Check as stated in item "FOCUS SERVO SAWTOOTH WAVE
No
FAILURE".
Check the periphery of IC802 and CNW802/CNS802. Is it normal?
No
The optical pickup is faulty.
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Yes
Yes