LG FA162 Service Manual page 40

ELECTRICAL TROUBLESHOOTING GUIDE OF CD PART
5-3. READING OK CHECK #C (= "NO DISC" DISPLAY)
#C
Is 3.3 V applied
to Pin10 of CN401 laser supply
voltage check
YES
Check connector
CN401 line.
YES
Defective pick-up laser part.
5-4. READING OK CHECK #D (= "NO DISC" DISPLAY)
#D
Does
SP+ waveform
appear at (IC400 Pin11)
waveform#4 spindle motor
drive wave.
YES
Check connector
CN403 line.
YES
Defective pick-up spindle motor.
Is 3.3 V applied
NO
to Pin30,36,39,41,61,68,75
of IC401 RF IC supply
voltage check
Is 2.3 V
Pin18(LDO) of IC401
laser control voltage
check
Defective IC400.
NO
Defective CN401.
Does
NO
SPIN waveform
appear at (IC400 Pin6)
waveform #4 spindle dirve
wave
Defective IC400.
NO
Defective CN401.
3-21
NO
YES
NO
YES
NO
YES
Defective IC400.
Defective IC401.
Defective IC401.