Brother HL-3450CN Service Manual page 325

CHAPTER 8 TROUBLESHOOTING
I-23
Phenomenon
A blank page (no print at all) is output or a specific color is missing (not printed) as shown in
print sample (23) of Page
Main Causes
(1) Laser light path is blocked by paper or other material stuck at the opening of the laser
unit.
(2) The TR cam clutch is broken (not functioning).
(3) There is no belt bias voltage (CBV).
(4) There is no output from the high-voltage power supply unit (HVU) due to breakdown.
Countermeasures
(1) Confirm that there are no foreign objects stuck in the opening of the laser unit.
(2) Replace the TR cam clutch with a new one. (See
(3) Replace the OPC belt cartridge with a new one. (See
(4) Replace the high-voltage power supply unit with a new one. (See
7.)
I-24
Phenomenon
Printed image is partially missing as shown in
that the fusing is insufficient.
Main Causes
(1) Wrong selection of print media (label or envelope, etc.) at the Host (driver) side.
(2) Recommended paper is not being used.
(3) Double-feed paper.
(4) Failure of the fusing unit.
Countermeasures
(1) Adjust the mode of Host side to suit the print media in use.
(2) Use the recommended paper.
(3) Fan the paper before loading in the media cassette.
(4) Replace the failed fusing unit with a new one. (See
White Print
8-46.
Insufficient Fusing
Section 4.1.7 of Chapter
Section 4.1 of Chapter
print sample (24) of Page
Section 4.2 of Chapter
8-62
7.)
6.)
Section 4.3.3 of Chapter
8-46. This proves
6.)