Sharp XL-1200 Service Manual page 30

XL-1200/1200C
• Focus servo sawtooth wave failure.
Is sawtooh wave output to the pin 48 (FOO) of IC802 ?
Yes
Is +6.2V applied to the pins 21 and 22 (VCC) of IC804 ?
Yes
Is sawtooth wave obtained between pins 26 and 27 of IC804 ?
Yes
Is sawtooth wave obtained between pins 13 and 16 of
CNP802/CNW3 ? (as shown above)
Yes
CNP802/CNW3 connection failure or optical pickup failure.
• Spindle motor clv servo failure.
Is following wave output to the pin 55 (DMO) of IC802 when
the CD TEST MODE "STEP 3" is changed to " STEP 4" ?
Yes
DMO
Is above wave obtained between pins 11 and 12 of IC804 ?
Yes
Is above wave obtained between pins 9 and 12 of CNP802/
CNW3 ?
Yes
CNP802/CNW3 connection failure or optical pickup failure.
1.5~2.5sec
1.5~2.5sec
IC802 is faulty.
No
Check the PWB pattern between emiter of Q607 and IC804.
No
Is +5V applied to the pin 7
No
(MUTE) of IC804 ?
Yes
Check the PWB pattern between pin 48 (FOO) of IC802 and pins
24 and 25 of IC804. If OK. IC804 is faulty.
Check the PWB pattern between CNP802/CNW3 and IC804.
No
Check the procedure in "HF ERROR".
No
If OK. IC802 is faulty.
Check the PWB pattern between pin 55 (DMO) of IC802 and pins
No
9 and 10 of IC804. If OK. IC804 is faulty.
Check the PWB pattern between CNP802/CNW3 and IC804.
No
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Check the PWB pattern
between pin 7 of IC804
No
and pin 60 (CD STB) of
IC701.