Trouble Shooting (Cd Section); Cd Fails To Operate - Sharp MD-R3 Service Manual

MD-R3

CD fails to operate

If the objective lens of optical pickup is contaminated, CD may fail to operate. At first clean the objective lens, and check playback
operation. If CD does not operate persistently, check as follows.
If dust or foreign substance is accumulated on the pickup lens, playback is disturbed and TOC (content of item) is not displayed.
Before adjusting check whether the lens is clean. If the lens is contaminated, treat it as follows.
Turn off power supply, impregnate the lens cleaning paper with a small quantity of isopropyl alcohol, and gently wipe the lens with
it with due care so that the lens is not damaged.
At this time do not contact directly the lens with our finger.
Set disc, turn on power supply, press the CD (stop) button, and check voltage of BI851/CNS552A/B.
Is voltage specified in wiring diagram applied?
Does laser light in the CD TEST mode 1?
Does process proceed from the CD TEST mode 1 to 2?
Does the disc motor rotate normally when the mode is
changed from the CD TEST mode 2 to 3?
Is output of pin 3 (HF) of TP751 flat in the CD TEST mode 4?
Is sound output when the CD TEST mode 5 is set and the optical
pickup is moved to the
with (skip) (skip)?
Is initialization performed when power is once turned off and then
turned on?
Are tracks played back sequentially with
Is playback performed for several tens seconds after playback is
started?
Normal

TROUBLE SHOOTING (CD SECTION)

Yes
Yes
Yes
Yes
Yes
track existing position
Yes
Yes
(skip)?
Yes
Yes
Check the main unit side power circuit.
No
Check as stated in item "Laser does not light".
No
Check as stated in item "Focusing failure".
No
Check as stated in item "Disc motor CLV servo failure".
No
Check as stated in item "HF trouble"
No
Does the slide motor run?
No
Check as stated in item
"Sound is not output".
Does the optical pickup
No
return to the inner position?
Yes
The optical pickup IN switch
is defective (ON state).
Check as stated in item "Track search is disabled."
No
Check as stated in item "Slide servo fails to run"
No
– 62 –
Check as stated in item "Slide
No
motor fails to run"
Is the optical pickup In
switch in OFF state?
No
OFF ON
Check The optical
microcomputer pickup In
switch is
PWB.
defective.