Troubleshooting For Control Panel Problems; Nothing Is Displayed On The Lcd; Nothing Is Displayed On The Led; Unable To Perform Panel Operation - Brother DCP-7090 Service Manual

4.6 Troubleshooting for Control Panel Problems

4.6.1 Nothing is displayed on the LCD

<User Check>
• Turn the power switch OFF and then back ON again.
• Unplug the AC cord and then plug it again.
Step
1
2
3
4
5
6
7
8
9

4.6.2 Nothing is displayed on the LED

<User Check>
• Turn the power switch OFF and then back ON again.
Step
1
2
3
4

4.6.3 Unable to perform panel operation

<User Check>
• Turn the power switch OFF and then back ON again.
Step
1
2
3
4
5
6
7
Cause
Connection failure of the
panel flat cable
Connection failure of the low-
voltage power supply harness
Connection failure of the LCD
flat cable
AC cord failure
Panel flat cable failure
LCD failure
Panel PCB ASSY failure
Low-voltage power supply
PCB failure
Main PCB failure
Cause
Connection failure of the key
PCB flat cable
Panel flat cable failure
Key PCB failure
Main PCB failure
Cause
Connection failure of the panel
flat cable
Connection failure of the touch
panel flat cable
Connection failure of the key
PCB flat cable
Panel PCB failure
Key PCB failure
Touch panel ASSY failure
Main PCB failure
Reconnect the panel flat cable.
Reconnect the low-voltage power supply
harness.
Reconnect the LCD flat cable.
Replace the AC cord.
Replace the panel flat cable.
Replace the panel unit.
Replace the panel PCB ASSY.
Replace the low-voltage power supply PCB
ASSY.
Replace the main PCB ASSY.
Reconnect the key PCB flat cable.
Replace the panel flat cable.
Replace the key PCB ASSY.
Replace the main PCB ASSY.
Reconnect the panel flat cable.
Reconnect the touch panel flat cable.
Reconnect the key PCB flat cable.
Replace the panel PCB ASSY.
Replace the key PCB ASSY.
Replace the panel unit.
Replace the main PCB ASSY.
2-100
Remedy
Remedy
Remedy
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