LG GCC-4520B Service Manual page 54

Recognition Fail Case 1:
CD-ROM Fail
Check Pickup Read Power
was 0.8 ~1.3mW?
YES
Does Focus Servo
operate normally?
YES
Check Pickup
RF signal (RFO+) was
500~900mVpp?
YES
Check RFOP
waveform (IC200 Pin 30) was
1300~1700mVpp?
YES
Check after replacing IC100.
It is OK?
YES
OK
Recognition Fail Case2 :
Blank CD-R/RW
Is there ATFG (IC200 pin65)
signal?
NO
Replace IC200.
NO
Go to "LD CHECK".
NO
Go to "Focus Servo is unstable".
NO
Check the Pick-up FFC and CN101.
Replace the Pick-up unit.
NO
Replace IC200.
NO
Go to "Tracking Servo is unstable".
YES
Is there WOBSI (IC100 174)
signal?
NO
Check the connection between
IC100 and IC200.
YES
Replace the IC100.
57