Sharp XL 1700 - Executive Microsystem Service Manual page 38

XL-1700/1700C
• Focus servo sawtooth wave failure.
Is sawtooh wave output to the pin 33 (FOO) of IC801 ?
Yes
Is +7.0V applied to the pins 21 and 22 (VCC) of IC803 ?
Yes
Is sawtooth wave obtained between pins 17 and 18 of IC803 ?
Yes
Is sawtooth wave obtained between pins 13 and 16 of
CNP801/CNW801 ? (as shown above)
Yes
CNP801/CNW801 connection failure or optical pickup failure.
• Spindle motor clv servo failure.
Is following wave output to the pin 41 (DMO) of IC801 when
the CD TEST MODE "STEP 3" is changed to " STEP 4" ?
Yes
DMO
Is above wave obtained between pins 1 and 2 of IC803 ?
Yes
Is above wave obtained between pins 9 and 12 of CNP801/
CNW801 ?
Yes
CNP801/CNW801 connection failure or optical pickup failure.
1.5~2.5sec
1.5~2.5sec
IC801 is faulty.
No
Check the PWB pattern between pin emitter of Q605 and IC803.
No
Is +5V applied to the pin 7
No
(MUTE) of IC803 ?
Yes
Check the PWB pattern between pin 33 (FOO) of IC801 and pins
19 and 20 of IC803. If OK. IC803 is faulty.
Check the PWB pattern between CNP801/CNW801 and IC803.
No
Check the procedure in "HF ERROR".
No
If OK. IC801 is faulty.
Check the PWB pattern between pin 41 (DMO) of IC801 and pins
No
9 and 10 of IC803. If OK. IC803 is faulty.
Check the PWB pattern between CNP801/CNW801 and IC803.
No
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Check the PWB pattern
between pin 7 of IC803
No
and pin 66 (CD STB) of
IC701.