LG FLATRON L172WT Service Manual page 19

4. NO RASTER ON TV SIGNAL INPUT
POWER CHECK OF TUNER(TU701) : L701(33V), L702(5V)
POWER CHECK OF VPC3230(U203) :L205(5V), L213(3.3V)
POWER CHECK OF GM1501(U402)
CHECK CONNECTION OF TV
TUNER AND ANTENNA
CHECK TV CH
YES
CHECK VPC3230(U203) I/O
SIGNAL
YES
CHECK GM1501(U402)
NO RASTER ON TV SIGNAL
NO
NO
NO
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SELECT AUTO CH OF OSD
CHECK THE PERIPHERAL IC
OF VPC3230(U203)
CHECK THE PERIPHERAL IC
OF GM1501(U402)