Ricoh Pro c751ex SC590-03

[Wild Bill]

[Ruta56c]

Re: Ricoh Pro c751ex SC590-03

Service manual says:
"SC590-3Stepper Motor Error 3
A stepper motor controlled by the TDCU on the back of the machine has
failed."

"Note:
• Look at the Point-to-Point diagram to determine which motors the
referenced board controls."

If to look on p-to-p diagram you'll see there are only two stepper motors, connected to that board:
STM1 Duplex/Inverter Motor
STM22 Pressure roller Lift Motor

Sometimes motor error doesn't mean the motor failure - It can be a failure of a sensor that senses the position of an object driven by the motor.

Hope this would help