[ 7 ] Troubleshooting of the control panel; User Check - Page 242

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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.