Samsung CLP-770ND Service Manual page 93

Contamination on back of page
The back of the page is contaminated.
Description
Cause and Check Point
Dirty registration roller, pressure roller, feed roller, etc.
Any dirty rollers through the path of the paper.
Dirty PTB belt or damaged PTB belt.
Dirty feed guide, or any paper delivery guide.
Dark or Black image
The back of the page is contaminated.
Description
Cause and Check Point
No charging voltage in the HVPS
Poor contact between toner cartridge and set contacts.
HVPS is defective.
Blank Page
Description Blank page is printed.
Cause and Check Point
Bad contacts from OPC drum and/or toner cartridge to
ground.
Not working the LSU
Not working the developing bias voltage on HVPS
Service Manual
Alignment & Troubleshooting
Identify the roller which may cause the problem by
comparing the period of the contamination on images
with the size of rollers. Clean any dirt from the roller or
replace the dirty roller.
Clean PTB or replace the PTB unit.
Clean the part which cause the contamination.
Check the connecting state between the Main PBA and
HVPS. Reconnect the harness.
Clean the contacts as necessary. Replace any
deformed or damaged contacts.
Replace the HVPS.
Check the terminal of Ground-OPC.
Check the connecter of LSU
Check the HVPS B'd and replace it.
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Solution
Solution
Solution
Samsung Electronics