SHARP QTCDWRD
Service Manual

QT-CD180H/QT-CD180W
� Focus failure.
Does the optical pickup move up and down when the disc is removed ? Yes Check as stated in item "FOCUS SERVO SAWTOOTH WAVE FAILURE".

No

Is the following waveform output at the pin 62 (FEI) of IC802 when the disc is set ? Yes
pin 62 (FEI)

No

Check the periphery of IC801 and BI801/CNS801. Is it normal ? Yes

The optical pickup is faulty.

pin 86 (FOO) pin 63 (SBAD)

Is the waveform shown above input at the pin 63 (SBAD) of IC802 ? Yes

No

Check the pattern between pin 13 of IC801 and pin 63 of IC802. Check the periphery of IC801 and BI801/CNS801.

IC801 is faulty.

� Focus servo sawtooth wave failure.
Is sawtooh wave output to the pin 66 (FOO) of IC802 ? Yes IC802 is faulty.

No

1.5~2.5sec

Is +8.1V applied to the pins 21 and 22 (VCC) of IC803 ? No Yes

Check the PWB pattern of IC803.

Is sawtooth wave obtained between pins 17 and 18 of IC803 ? Yes

No

Check the PWB pattern of IC803.

1.5~2.5sec

Is sawtooth wave obtained between pins 3 and 4 of BI801/ CNS801 ? (as shown above) Yes

Check the PWB pattern between BI801/CNS801 and IC803. No

BI801/CNS801 connection failure or optical pickup failure.

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