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[ 7 ] Troubleshooting of the control panel
L-1
Nothing is displayed on the LCD.
User Check
(1) Verify if the power switch is turned off.
Possible cause Step Check Result Remedy
Connection
between main
PCB and control
panel PCB
1 Main PCB and
control panel PCB
are properly
connected
No Fix the connector properly.
Harness between
main PCB and
control panel
PCB
2 Harness is damaged. Yes Replace the harness with a normal
part.
Connection
between main
PCB and low-
voltage power
supply PCB
3 Main PCB and low-
voltage power supply
PCB are properly
connected.
No Fix the connection properly.
Harness between
main PCB and
low-voltage
power supply
PCB LCD
4 Harness is damaged. Yes Replace the harness with a normal
part.
LCD 5 Replacement of LCD
solves the problem.
Yes Replace the LCD with a normal
part.
Control panel
PCB
6 Replacement of
control panel PCB
solves the problem.
Yes Replace the control panel PCB
with a normal part.
Low-voltage
power supply
PCB
7 Replacement of low-
voltage power supply
PCB solves the
problem.
Yes Replace the low-voltage power
supply PCB with a normal part.
Main PCB 8 Replacement of main
PCB solves the
problem.
Yes Replace the main PCB with a
normal part.