Sharp XL 1700 - Executive Microsystem Service Manual page 37

• Laser failure.
Is +7.2V applied to the pin 1 of CNW805 ?
Yes
Is +5V applied to the cathode side of ZD801 ?
Yes
Is +5V applied to the pin 64 (VDD) of IC801 ?
Yes
Is +3.3V applied to the pin 1 (VCC) of IC802 ?
Yes
Is 0V applied to the pin 38 (SEL) of IC801 ?
Yes
Is approx. 2V applied to the collector of Q801.
Yes
Check CNP801/CNW801. 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 29 (FEI) of IC801
when the disc is set?
Yes
Is the waveform shown above input at the pin 30 (SBAD) of
IC801?
Yes
IC802 is faulty.
Check the PWB pattern between emitter of Q605 and CNP805/
No
CNW805.
Check the peripheral parts of ZD801,C820 and C821.
No
Check the PWB pattern between cathode side of ZD801 and pin
No
64 of IC801.
Check the PWB pattern between collector of Q802 and pin 1 of
No
IC802.
Does the laser come on when pattern cut between pin 8 (SEL) of
No
IC802 and pin 38 (SEL) of IC801 ?
No
Check the PWB pattern between IC701 and IC801 (BUCK/CCE/
BUS0~3)
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 CNP801/CNW801. Is it normal?
No
The optical pickup is faulty.
Check the pattern between pin 12 of IC802 and pin 30 of IC801.
No
Check the periphery of IC802 and CNP801/CNW801.
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XL-1700/1700C
Yes
Yes