Read Sharp QT-CD250 (serv.man6) Service Manual online
QT-CD250H/W
– 22 –
• Focus servo sawtooth wave failure.
Is +7.5V applied to the pins 1 and 30 (VCC) of IC803 ?
Is sawtooh wave output to the pin 66 (FOO) of IC802 ?
IC802 is faulty.
No
Yes
Yes
Is sawtooth wave obtained between pins 20 and 21 of IC803 ?
No
Check the PWB pattern of IC803.
Check the PWB pattern of IC803.
No
Is sawtooth wave obtained between pins 3 and 4 of BI801/
CNS801 ? (as shown above)
CNS801 ? (as shown above)
Yes
Check the PWB pattern between BI801/CNS801 and IC803.
No
BI801/CNS801 connection failure or optical pickup failure.
Yes
• Spindle motor clv servo failure.
Is above wave obtained between pins 5 and 6 of IC803 ?
Is following wave output to the pin 72 (DMO) of IC802 when
the Function is changed to "PLAY" from "STOP" ?
the Function is changed to "PLAY" from "STOP" ?
No
Yes
Check the procedure in "HF ERROR".
If OK. IC802 is faulty.
If OK. IC802 is faulty.
Check the PWB pattern between pin 72 (DMO) of IC802 and pins
5 and 6 of IC803. If OK. IC803 is faulty.
5 and 6 of IC803. If OK. IC803 is faulty.
No
Is above wave obtained between pins 5 and 6 of BI803/
CNS803 ?
CNS803 ?
Yes
Check the PWB pattern between BI803/CNS803 and IC803.
No
BI803/CNS803 connection failure or optical pickup failure.
Yes
DMO
1.5~2.5sec
1.5~2.5sec
Click on the first or last page to see other QT-CD250 (serv.man6) service manuals if exist.