Troubleshooting Of The Control Panel; Nothing Is Displayed On The Lcd; The Control Panel Does Not Work; Lamp Malfunction - Brother DCP-7055 Service Manual

3.11 Troubleshooting of the Control Panel

3.11.1 Nothing is displayed on the LCD

User Check
• Verify if the power switch is turned off.
Step
1 AC cord failure
Harness connection failure of panel
2
PCB ASSY
Harness connection failure of LCD
3
and panel PCB
4 LCD failure
Power switch holder failure
5
Low voltage power supply PCB
6
failure
7 Panel PCB failure
8 Main PCB failure

3.11.2 The control panel does not work

User Check
• Check whether the function lock is not set.
• Turn the power off and on.
Step
1 Panel unit assembling failure
Connection failure between main
2 PCB and panel PCB
3 Rubber key failure
4 Panel PCB failure
5 Main PCB failure

3.11.3 Lamp malfunction

Step
Connection between main PCB and
1 panel PCB
2 Panel PCB failure
3 Main PCB failure
Cause
Cause
Cause
2-99
Remedy
Replace the AC cord.
Reconnect the panel PCB ASSY harness.
Check the harness connection between
the LCD and panel PCB, and reconnect it.
Replace the LCD.
Replace the power switch holder.
Replace the low voltage power supply
PCB ASSY.
Replace the panel PCB ASSY.
Replace the main PCB ASSY.
Remedy
Re-assemble the panel unit.
Connect the connector between the main
PCB ASSY and panel PCB ASSY
correctly.
Replace the rubber key.
Replace the panel PCB ASSY.
Replace the main PCB ASSY.
Remedy
Connect the connector between the main
PCB ASSY and panel PCB ASSY
correctly.
Replace the panel PCB ASSY.
Replace the main PCB ASSY.
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