Ricoh PCU10, Service Training Manual

Page: 130 / 195

2.12.8 Fusing temperature control
When the main switch is turned ON, the heater comes ON and temperature rises. When the
thermistor detects a temperature of 175
o
C, the main motor turns on and the machine enters idling
mode. The fusing temperature is controlled within 175°C and 180
o
C.
2.12.9 Service call
SC1 Problem:
Fusing high temperature (fusing unit temperature is 230
o
C or more for 2 seconds).
Cause: Failed thermistor due to short circuit, or relay short circuit.
SC2 Problem: Fusing low temperature (fusing unit temperature is 130
o
C or less for 20 seconds).
Cause:
Fusing lamp broken, thermistor failed, fusing lamp not connected, door switch broken, or re-
lay failure.
SC3 Problem:
Fusing temperature not stabilized (temperature not higher than 175
o
C 10 minutes after the
main switch is turned ON).
Cause: Fusing lamp broken, thermistor failure due to short circuit, door switch broken, or relay fail-
ure.
SC4 Problem: Thermistor failure
Cause: Thermistor broken (open circuit), fusing connector failure (fusing unit not set properly).
Main Switch
Fusing stabilized
Idling mode
Start key turns green
(copy stand-by)
Fusing lamp
Fusing
temperature
Fusing 1 July 1994
2-94