If you want to enter in SP Mode (Service Progrm Mode) on Ricoh MP 2501 sp model, press on the keyboard 1 > 0 > 7 than press and hold "C" key for some seconds till you see the cahanged display. Go to Sistem...
If you need to enter in Service Program mode on RICOH MP2553SP/3053/3053SP/3353/3353SP series, follow the instructions:
-Turn on the main power switch ON.
-Press CA
-Press 806182
-Press and hold C key abot 3-4 sec.
You can watch this procedure on this video for better understanding:
https://www.youtube.com/watch?v=xLLPvOBGfm8