Repair Flow Chart:Trouble Condition
Green Power is on,but LCD backlights are not on.
Backlights do not turn on, or only turn on and back off.
Power LED turns ON,
but LCD backlight is not ON
or only turned ON and then
back OFF.
On analog signal board:
Is the “BL_SW” voltage (5V)
Supplied from “K17 Pin13”?
On Power board:
Is the 0V supplied from “CN3 Pin10”
during LED on time?
Panel is broken.
Replace “Panel”.
On digital board:
Is 3.3V supplied to”K5A Pin19” ?
Digit board is not working.
Replace “digital board”.
On Power board:
Is the 50V sine wave (RMS) supplied from “CN3 Pin 1/2”
Power board is not working.
Replace “Power board”.
Confirm wire harness connection
between analog board &Power board
and between Power board and panel .
Panel is not working
Replace panel.
Replace “analog board and
wire harness”.
No:0V
No:0V
Yes:5V
Yes:3.3V
Yes:0V
No:over 0.1V
No:0V
Yes:+/-50V sine wave(RMS)
Page 2
See TABLE *1.0
See TABLE *3.0
See TABLE *4.0
“ CN3 Pin 4/5”
See TABLE *2.0
and 50V sine wave (RMS) supplied
Page 2
