Sharp QT-CD180(BL) Service Manual page 18

QT-CD180
• Laser failure.
Is +5V applied to the emitter of Q204 ?
Yes
Is +5V applied to the collector of Q204 ?
Yes
Is +5V applied to the pin 75 (VDD) of IC802 ?
Yes
Is +5V applied to the pin 1 (VCC) of IC801 ?
Yes
Is +0V applied to the pin 74 (SEL) of IC802 ?
Yes
Is approx. 1.8V applied to the collector of Q801.
Yes
Check BI801/CNS801. 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 62 (FEI) of IC802
when the disc is set ?
Yes
pin 62
(FEI)
pin 86
(FOO)
pin 63
(SBAD)
Is the waveform shown above input at the pin 63 (SBAD) of
IC802 ?
Yes
IC801 is faulty.
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No
Check the peripheral parts of IC803 and Q204.
No
No
Check the PWB pattern between collector of Q204 and pin 1 of
No
IC801.
Check the laser come on when pattern cut between pin 8 (SEL) of
No
IC801 and pin 74 (SEL) of IC802.
Check the peripheral parts of IC801 and Q801. If it is normal, the
No
optical pickup is faulty.
No
Check the periphery of IC801 and BI801/CNS801. Is it normal ?
No
The optical pickup is faulty.
Check the pattern between pin 13 of IC801 and pin 63 of IC802.
No
Check the periphery of IC801 and BI801/CNS801.
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Check the PWB pattern of Q204.
Check the PWB pattern between collector of Q204 and pin 75 of
IC802.
Check as stated in item "FOCUS SERVO SAWTOOTH WAVE
FAILURE".
Yes