Sharp MD-R3H Service Manual page 65

• Spindle motor CLV servo failure
Does the spindle motor run in the CD TEST mode3?
Does eye pattern appear on the pin 3 of TEST point TP751?
(Unclear waveform is allowable.)
Is eye pattern Vp-p 1.5V input into the pin 19 of IC800?
IC800 failure. (check the peripheral parts and then replace)
• Slide motor fails to run.
S et the CD TEST mode, press the
button, and check whether slide feed signal is output between
the pin 20 of IC750 and 1/2VCC.
Is slide feed signal output between the pins 11 and 12 of
IC700?
Is slide feed voltage applied to both ends of slide motor?
Check the slide motor. Apply DC2.0V to the slide motor terminal. If the slide motor fails to run, it is defective.
• Slide servo fails to operate.
Is slide control voltage waveform (shown right) input into the
pin 18 of IC750 during playback?
Is waveform shown right output to the pin 20 of IC750?
The slide servo system is not defective. Redo check.
Yes
(Extremely high speed
rotation)
Yes
Yes
(skip) (skip)
Yes
Yes
Yes
Yes
Yes
Is voltage generated for about 0.3 to
No 1.5 sec between the pins 17 and 18
of IC700 when the mode is changed
from the CD TEST mode 2 to 3?
No
Is the pin 37 of IC800 in High state
for 0.3 to 1.5 sec when the CD
TEST mode 2 is changed to 3?
Does pulse appear subsequently?
Yes
IC700 failure or wire breakage.
Check again for contamination of objective lens of optical
No
pickup. If it is contaminated, clean.
Check connection between the pin 41 of IC750 and the pin 19
of IC800. If it is normal, the optical pickup is defective.
Check the PWB pattern and C806.
No
Check connection of peripheral parts of IC750. If it is normal,
No IC750 is defective.
Check connection between the pin 25 of IC700 and the pin 20
No
of IC750.
Check the PWB pattern.
No
Check connection of parts between the pins 17 and 18 of IC750
and the PWB pattern.
No
IC750 is defective.
No
– 65 –
MD-R3H
Spindle motor failure
or wire breakage.
Yes
0.3~1.5 sec.
IC800 is defective.
No
5V
0.3~1.5 sec.
Rotation cycle of motor
Voltage varies depending
on eccentricity.
Slide control voltage waveform