Samsung SF-76x series Service Manual page 89

The toner level is not even on the toner cartridge roller due
to the bad doctor blade.
8) Background
Description : Light dark background appears in whole area of the printing.
Check and cause
Does recycle paper be used?
The life of the toner cartridge has been expired
The output from the SMPS/HVPS is abnormal.
9) Ghost
Description : Ghost occurs at 62.9 mm intervals of the OPC drum.
Check and cause
The high voltage terminal is contaminated.
The life of the toner cartridge has been expired
The life of the transfer roller has been expired.
10) Stains on back of page
Description : The back of the page is stained.
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4. Alignment and Troubleshooting
Replace the toner cartridge.
Solution
Use the proper papers.
Replace the toner cartridge.
Replace the SMPS/HVPS board.
Solution
Clean the high voltage terminals.
Replace the toner cartridge.
Replace the transfer roller.
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