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MD-R3H
• Laser does not light
No
IC901 is defective.
Is +1.8V applied to the collector of Q701.
Yes
Is 5V applied to the pin 13 CD LD ON terminal of IC901?
Yes
Is +4.0V applied to the emitter of Q751?
No
Is +5V applied to the C751 side of
R753?
No
R753 is defective.
Yes
Check the pin 2 of BI851/CNS552A/B, and check +5V line of
SERVO.
No
Is +3.2V applied to the base of
Q751?
Check between the
base of Q751 and
the pin 6 of IC750.
No
Yes
Q751 is defective.
Is +1.8V applied to the pin 8 of CNP751?
PWB pattern breakage between Q751 and pin 8 of CNP751
No
Yes
Yes
Check CNP751. If it is normal, the optical pickup is defective.
• Focusing failure
No
Remove disc, and check whether the optical pickup lens
moves up and down.
Check as stated in item "Triangular wave for focus servo is
not output".
Yes
Set disc, and check whether the following waveform appears
on the pin 8 of IC750.
No
Set disc, and check whether the following waveform appears
on the pin 8 of IC750.
Yes
IC750 is defective.
8 PIN
22 PIN
(FE OUT)
(FS OUT)
• HF trouble
Does output (tracking error signal) appear on the pin 4 of
TP751 in the CD TEST mode 3?
Check CNP751. If it is normal, the optical pickup is defective.
Abnormal
Normal
Yes
Adjust again tracking gain.
I
s the tracking gain adjusting VR752 set to minimum?
No
Check the peripheral parts of IC750. If it is normal, IC750 is
defective.
Does tracking output appear on the pin 17 of IC750 in the CD
TEST mode 4?
No
No
Check the peripheral parts of IC700. If it is normal, IC700 is
defective.
Does output appear between the pins 26 and 27 of IC700?
Yes
Yes
Check connection of optical pickup wire between IC700 and CNP751. If it is normal, the optical pickup is defective.