Front Panel Troubleshooting Flow - LG LST-3100A Service Manual

6. FRONT PANEL Troubleshooting Flow

1) If front panel board is not working
START
YES
The IC 5V power is supplied normally?
YES
The IC -28, -24, -21.5V powers are
supplied normally?
YES
The clock #1 operates normally?
The signal #2 operates normally?
YES
The signal #3 operates normally?
YES
END
NO
Check IC100(13), IC100(43),
IR100(2)
NO
Check Connector P101(3), P101(2),
P101(1) voltage : -28, -24, -21.5V
NO
Check IC100(5) clock waveform
: See FIG. 01
NO
Check IC100(8) clock waveform
: See FIG. 02
NO
Check IC100(42) clock waveform
: See FIG. 03
3-32
voltage : 5V