LG LF-U850D Service Manual page 9

FUNCTION INPUT UNFELT (IC601 BU4052)
CD FUNCTION
YES
PN805 ASSEMBLY STATUS CHECK
YES
IC601 (BU4052)5,14PIN INPUT WAVEFORM CHECK
YES
IC601 (BU4052)3,13PIN OUTPUT WAVEFORM CHECK
YES
IC602 (MC4580) 2,6PIN INPUT WAVEFORM CHECK
YES
NORMAL OPERATION
U-COM (IC301)83PIN,84PIN COMMUNICATION CHECK.
NO
MUTING MODE CHECK IC301 REPLACEMENT
NO
C601 (BU4052)16PINVDD,8PIN VSS POWER CHECK
REPLACE APPROPRIATE PARTS
NORMAL
NO
IC602 (MC4580) 4PIN VSS,8PIN VDD POWER CHECK.
REPLACE APPROPRIATE PARTS
NORMAL
NO
- 2-3 -
YES
YES
YES
YES
FRONT CN304 MAIN PCB PN302 FFC WIRE
contact and assembly status check
YES
NORMAL
REFER TO SMPS
TROUBLESHOOTING
REPLACE FAULTY PARTS