Tuner/If Circuit - LG RCT689H Service Manual

VCR ELECTRICAL TROUBLESHOOTING GUIDE

6. TUNER/IF CIRCUIT

6-1. No Picture on the TV screen
No Picture
on the TV Screen
YES
Does the
Video signal appear at TU701
Pin9?
YES
Does the
Video signal appear at IC401
Pin8?
YES
Does the
Video signal appear at IC901
Pin2?
YES
Check the Jack(JK905)
Is 5V
NO
applied to TU701
Pin2?
Is 3.3V
applied to TU701
Pin3,26?
Is 1.8V
applied to TU701
Pin7?
Is 1.2V
applied to TU701
Pin27?
Does the Clock,
Data signal appear at TU701
Pin23,24?
Check the IC703.
NO
Check the Pattern between
TU701Pin9 and IC401 Pin8.
NO
Check the DVD Board
Video Path.
3-14
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
Check 5V line.
Check 3.3V line.
Check the IC803.
Check the IC701.
Check the IICClock,Data signal
of the IC601 Pin17,18.