Samsung CLX-8640 series Service Manual page 314

4. Troubleshooting
To enter SVC mode, press 1,2,3 number keys simultaneously. When the password dialog box appears, enter
"1934" and press the "OK" button.
16)Select "Roller" (INFORMATION > Supply Status > Field Replacement Unit > Roller)
17)Select "P/up roller MP". The "RESET" button will be activated. Click "RESET" to clear the MP pick up roller.
18)Exit SVC mode by pushing the home button.
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