Samsung ML-2851ND/XAZ Service Manual page 101

7) No error LED when the cover is open
Description: The Error LED does not come on even when the printer cover is open
1. Check the connector and
circuit of the cover switch department
in the Main Control board.
Service Manual
Alignment & Troubleshooting
Perform DCU test
1. Check the insertion of the
Cover Open S/W Connect.
2. Replace the Main Control
board or Cover Open S/W.
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Samsung Electronics