Ricoh M016 Service Manual page 153

Video thermistor error
At power on, the temperature sensor in the optics unit detected a temperature
lower than -30°C for more than 4 sec.
-or-
It detected a temperature higher than 105°C for more than 1sec.
268
Thermistor disconnected (causes extremely low temperature reading)
Thermistor damaged and short circuited (causes extremely high temperature
reading)
1. Turn the machine's main power off, and then on.
2. Replace the thermistor.
SC 4xx (Image Transfer and Transfer Error)
Bias leak
An error signal is detected for 0.2 seconds when changing the development unit.
491
Defective transfer roller
Defective high voltage power pack
1. Turn the machine's main power off, and then on.
SM
Service Call Conditions
6-3 M016/M017