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HL-7050 SERVICE MANUAL
6-37
I-3
Completely blank
Possible cause
Step
Check
Result
Remedy
Ground
contacts
Developing bias
contact failure
1
Are the developing bias
contacts between the printer
body and drum unit dirty?
Yes
Clean the electrodes
at both sides.
(4)
Drum unit
2
Are the drum shaft and drum
electrode of the printer body
connected correctly?
Yes
Clean the shaft and
the electrode.
(1)
No
Check the connection
between the shaft and
the electrode.
(1)
Drum unit failure
3
Is the problem solved after
replacing the drum unit?
Yes
Replace the drum
unit.
Toner cartridge
failure
4
Is the problem solved after
replacing the toner cartridge?
Yes
Replace the toner
cartridge with a new
one.
Scanner
harness
connection
failure
5
Is the scanner harness
connected securely?
(Check if there is any play in
the connection.)
No
Reconnect the
connector correctly.
Main PCB
failure
6
Are printing signals being input
to the laser unit?
Is the problem solved after
replacing the main PCB?
Yes
Replace the main
PCB.
Laser unit failure
7
Is the scanner interlock lever
damaged?
Yes
Replace the laser unit.
Is the scanner mirror broken or
loose?
No
Replace the high-
voltage power supply
PCB.
Summary of Contents for HL-7050 Series
Page 29: ...HL 7050 SERVICE MANUAL 1 15 ...
Page 295: ...A 1 APPENDIX 1 CONNECTION DIAGRAM HL 7050 ...
Page 296: ...APPENDIX 2 MAIN PCB CIRCUIT DIAGRAM HL 7050 1 9 ...
Page 297: ...APPENDIX 3 MAIN PCB CIRCUIT DIAGRAM HL 7050 2 9 ...
Page 298: ...APPENDIX 4 MAIN PCB CIRCUIT DIAGRAM HL 7050 3 9 ...
Page 299: ...A 5 APPENDIX 5 MAIN PCB CIRCUIT DIAGRAM HL 7050 4 9 CODE NAME LJ9004001 B512149 CIR 4 9 ...
Page 300: ...A 6 APPENDIX 6 MAIN PCB CIRCUIT DIAGRAM HL 7050 5 9 CODE NAME LJ9004001 B512149 CIR 5 9 ...
Page 301: ...A 7 APPENDIX 7 MAIN PCB CIRCUIT DIAGRAM HL 7050 6 9 CODE NAME LJ9004001 B512149 CIR 6 9 ...
Page 302: ...A 8 APPENDIX 8 MAIN PCB CIRCUIT DIAGRAM HL 7050 7 9 CODE NAME LJ9004001 B512149 CIR 7 9 ...
Page 303: ...A 9 APPENDIX 9 MAIN PCB CIRCUIT DIAGRAM HL 7050 8 9 CODE NAME LJ9004001 B512149 CIR 8 9 ...
Page 304: ...A 10 APPENDIX 10 MAIN PCB CIRCUIT DIAGRAM HL 7050 9 9 CODE NAME LJ9004001 B512149 CIR 9 9 ...
Page 305: ...A 11 APPENDIX 11 ENGINE PCB CIRCUIT DIAGRAM HL 7050 1 3 CODE NAME LJ9016001 B512139 CIR 1 3 ...
Page 306: ...A 12 APPENDIX 12 ENGINE PCB CIRCUIT DIAGRAM HL 7050 2 3 CODE NAME LJ9016001 B512139 CIR 2 3 ...
Page 307: ...A 13 APPENDIX 13 ENGINE PCB CIRCUIT DIAGRAM HL 7050 3 3 CODE NAME LJ9016001 B512139 CIR 3 3 ...
Page 316: ...APPENDIX A 22 Fig A 2 Page counter is printed here This not printed in some countries ...