XL-55 (serv.man18). Troubleshooting - Sharp Audio Service Manual (repair manual). Page 6

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Yes

Is following sled feed signal input the pin 3 (VIN1) of IC804
when FF/REW key is pressed after the CD TEST MODE
"STEP 1" is seted?

Is sled feed voltage applied between both terminals of sled
motor?

No

C801 is faulty.

Check the CNW803/CNS803.

No

Yes

Check the CD mechanism (periphery of sled motor).
If the sled motor does not run when DC2.0V is applied to
both terminals of sled motor, the sled motor is faulty.

Yes

Is following sled signal output the pin 3 (VIN1) of IC804 during
playback?

Normal.

No

IC801 is faulty.

Does the sled motor run in FF/REW state when the SERVO
TEST MODE "STEP1" is set?

Is the following wave output to the pin 27 (TRO) of IC801
during track search in normal playback?

Is the following wave output to the pins 20(TEOUT) of IC802
during track search in normal playback?

Yes

Yes

No

Check as stated in item "SLED MOTOR OPERATION FAILURE".

No

IC801 failure.

No

Check the PWB pattern between pin 27 (TRO) of IC801 and pin
19 of IC804.
Check the PWB pattern between pins 17 and 18 of IC804 and
Optical pickup.
If OK.  Optical pickup failure.

Yes

Is the above wave output to the pins 33 (TE) of IC801 during
track search in normal playback?

No

Check the PWB pattern between pin 20 (TEOUT) of IC802 and pin
33  of IC801.  If OK. IC802 failure.

Normal.

Yes

Yes

Is following sled feed signal output the pins 1 and 2 of IC804
when FF/REW key is pressed after the CD TEST MODE
"STEP 1" is seted?

IC804 is faulty.

No

Is the following wave output to the pin 38 (/RFDET) of IC801
during track search in normal playback?

No

Check the PWB pattern pin 38 (/RFDET) of IC801 and pin 8 (ARF)
and pin15 (NRFDET) of IC802 .  If OK. IC802 failure.

Yes

TRO

TEOUT

TE

FF

REW

VIN1

VIN1

/RFDET

FF

REW

SL 

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