Brother HL-L8250CDN Service Manual page 131

4.6 Troubleshooting for Control Panel Problems
4.6.1 Nothing is displayed on the LCD/LED
< User Check >
- Turn the power OFF/ON.
Step
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Cause
The version of the panel
firmware and the main
firmware do not match.
(Model with touch panel)
Connection failure of the key
PCB flat cable
(Model with touch panel)
Connection failure of the
panel PCB harness
(Model without touch panel)
Connection failure of the LCD
flat cable
(Model without touch panel)
Connection failure of the
low-voltage power supply
PCB harness
AC cord failure
Key PCB flat cable failure
(Model with touch panel)
Panel control PCB failure
(Model with touch panel)
LCD unit failure
(Model with touch panel)
Key PCB failure
(Model with touch panel)
Panel PCB failure
(Model without touch panel)
LCD failure
(Model without touch panel)
Low-voltage power supply
PCB failure
Main PCB failure
Install the latest panel firmware and main
firmware.
Reconnect the key PCB flat cable.
Reconnect the panel PCB harness.
Reconnect the LCD flat cable.
Reconnect the low-voltage power supply
PCB harness.
Replace the AC cord.
Replace the key PCB flat cable.
Replace the panel control PCB ASSY.
Replace the LCD panel ASSY.
Replace the panel case ASSY.
Replace the panel PCB ASSY.
Replace the LCD.
Replace the low-voltage power supply PCB
unit.
Replace the main PCB ASSY.
2-108
Remedy
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