Samsung SL-M4080FX Service Manual page 197

2) Vertical White Line, Band
Description : White vertical voids occurs in the printed image.
Probable Cause
The paper is not the proper type.
The paper path is contaminated by toner residue, debris etc.
The toner cartridge is defective.
The transfer roller is contaminated or worn out.
The LSU window is contaminated.
The connection between the LSU and main board is
defective.
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Solution
Replace the paper.
Clean the paper path.
Replace the toner cartridge.
Replace the transfer roller.
1) Clean the LSU window.
2) Replace the LSU
1) Disconnect and reconnect the harness.
2) Replace the harness.
4. Troubleshooting
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