NRG / Ricoh error messages
SC 503 / 504
Remove paper from tray 3, switch off with red button and wait 10 seconds. Re-load with paper, ensuring that you do not overfill from line.
SC 501 / 502
Indicates that there is a piece of paper jammed at the rear of tray 3 or 4.
As above, also lifting out the complete tray.
SC551
Indicates that there is an issue with the fuser unit. Turn off the machine and wait 30 seconds, if it appears again, call Ricoh