Unico SQ Series - LCD No Backlight Troubleshooting

Trouble Shooting
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6.14 No backlight of LCD Display
Turn on, LCD display have no backlight
1. Solving wiring from LCD display
to J3 on SST8.417.100
2. Replace LCD display
AC 110V or 220V Power on?
Power cord connect OK?
Y
Fuse OK?
Y
Solving wiring from power
socket to the switch
power
Power on
N
Connect power cord
N
Replace fuse
N
Y
AC 1200V of J3 on PCB
SST8.417.100 OK?
AC 1200V of J3 on PCB
SST8.411.130A OK?
+5V of J1 on PCB SST8.411.130A
OK?
Y
+5V of Switch Power output OK?
N
AC 110V/220V input of Switch
Power OK?
Y
Replace switch power
N
Y
Y
Solving wiring from J1 on
PCB SST8.411.130A to
switch power
N
Replace PCB
SST8.411.130A
N
Solving wiring from J3 on
PCB SST8.411.130A to
SST8.417.100
N
Y