LG LF-U850D Service Manual page 11

TUNER FUNCTION
YES
TUNER MODULE (TU601) OPERATION CHECK
YES
IC601 (BU4052)2,15PIN 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
Refer to TUNER Troubleshooting and check power (2PIN12Vcheck)
NO
IC601 (BU4052)16PINVDD,8PIN VSS POWER CHECK
REPLACE APPROPRIATE PARTS
NORMAL
IC602 (MC4580) 4PIN VSS,8PIN VDD POWER
NO
CHECK.
REPLACE APPROPRIATE PARTS
NORMAL
NO
- 2-5 -
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