Brother DCP-7090 Service Manual page 101

 Error code 8903
The back cover sensor detected the open state when 2-sided printing is started (before the
registration of printing in the engine).
Error code 8904
The back cover sensor detected the open state during 2-sided printing (after the registration of
printing in the engine).
<User Check>
• Close the back cover correctly.
• Check that the duplex tray is set correctly.
Step
1 Duplex tray is not set correctly
2 Back cover sensor attachment failure
Breakage of boss that presses
3
the back cover sensor
Guide which pushes the back cover
4
sensor of the duplex tray is faulty
5 Back cover sensor failure
6 Main PCB failure
 Error code 8A01
The registration rear sensor detected that the paper fed was smaller or larger than the
specified size in duplex printing mode.
<User Check>
• Use appropriate paper (Letter to Legal).
Step
Registration rear actuator caught
1
in some sections of the machine
2 Registration rear sensor failure
3 Main PCB failure
 Error code 8C00
There is no paper set in the manual feed slot on the manual feed slot printing.
<User Check>
• Set the paper in the manual feed slot.
Step
Registration front actuator caught
1
in some sections of the machine
Connection failure of the
2 registration front/rear sensor
PCB harness
3 Registration front sensor failure
4 Main PCB failure
Cause
Cause
Cause
2-61
Remedy
Reattach the duplex tray correctly.
Reattach the back cover sensor.
Replace the back cover.
Replace the duplex tray.
Replace the eject sensor PCB ASSY.
Replace the main PCB ASSY.
Remedy
Reattach the registration rear actuator.
Replace the actuator holder ASSY.
Replace the main PCB ASSY.
Remedy
Reattach the registration front actuator.
Reconnect the registration front/rear
sensor PCB harness.
Replace the actuator holder ASSY.
Replace the main PCB ASSY.
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