LG 42PT250B Service Manual page 57

11. Analog TV Audio Trouble Shooting
Check video output
Y
Check Tuner Power
(5.0V, 3.3V, 1.2V)
Y
Check SIF Signal
TU1300 #9 Pin
Y
Check SIF Signal
Y
Follow procedure All source audio
trouble shooting
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Only for training and service purposes
N
Follow procedure analog TV video
trouble shooting
N
Replace one of L506/L509/IC600
& Recheck
N
Maybe Tuner(TU1300) has problems
Replace one of
N
C252/R246/R1332/Q1304/R1325
IC600 & Recheck
Maybe Mstar S7LR audio block has
N
problems.
Replace It
< SIF waveform – sample >
- Defend on the input signal.
LGE Internal Use Only