Brother HL-L5000D Service Manual page 92

 Error code 7800
The registration front sensor does not detect paper pass within the specified time after the
first side was printed in duplex printing mode.
<User Check>
• Remove the jammed paper.
• Close the back cover correctly.
• Attach the duplex tray correctly.
Step
Foreign object in the rear of the
1
machine or duplex tray
Twisted TT frame
2
Connection failure of the eject
3
motor harness
4 MX flapper attachment failure
5 MX switching solenoid failure
6 Duplex tray failure
7 Eject motor failure
Damaged gears in the paper
8
feeding system
9 Paper eject roller failure
10 Main PCB failure
Screws
Cause
Remove the foreign object.
Loosen the nine screws shown in the figure
below and tighten them again.
Reconnect the eject motor harness.
Reattach the MX flapper.
Replace the MX switching solenoid.
Replace the duplex tray.
Replace the eject motor.
Replace the main frame L ASSY.
Replace the paper eject roller.
Replace the main PCB ASSY.
Fig. 2-8
2-66
Remedy
Screws
Confidential