LG LM-M540 Service Manual page 18

READING OK CHECK #A (= "NO DISC" DISPLAY)
A A A A
DOES SL+ WAVEFORM APPEAR AT
( IC803 PIN14 AND PN802 PIN3)
WAVEFORM #2
SLED MOTOR WAVE
YES
CHECK PN802 CONNECTOR LINE
YES
NO
DOES SLIN WAVEFORM
APPEAR AT
( IC803 PIN 5)
WAVEFORM #2
SLED DRIVE WAVE
NO
NO
- 2-14 -
NO
DEFECTIVE IC801
NO
DEFECTIVE IC803
DEFECTIVE PN802
CONNECTOR
DEFECTIVE PICKUP
SLED MOTOR