Service Call Conditions - Ricoh FT5540 Service Manual

31 August 1989
Hot Roller Temperature
-- 220-240°C Upper Temperature Limit
If for any reason the hot roller temperature reaches the upper temperature
limit, the fusing thermistor resistance will become so low that the CPU detects
a thermistor short, resulting in a Call Service condition (Code "53"). This
prevents the roller from being damaged.
Maximum overshoot must be less than this value.
-- 215-220°C
-- 185°C
Operating Temperature
During the "Ready" condition, the temperature is kept at this value.
Machine Idle Run
-- 175°C
At this temperature, the caution beeper sounds five times. After 2 seconds,
the machine starts to idle.

12.8 SERVICE CALL CONDITIONS

Code #52: Thermofuse Blown
Definition
Lights if the thermofuse circuit opens or the fusing unit is not set correctly.
Observation
Code #52 is displayed when the main switch is turned on.
Points to Check
Confirm that CN102-B19 on the main board is +24 volts.
Confirm that the fusing unit is properly set.
Code #53: Thermistor Blown
Definition
Lights if the fusing thermistor opens.
Observation
Code #53 is displayed when the main switch is turned on.
Points to Check
Disconnect the white thermistor connector on the front side of the fusing unit. Check the
resistance of the thermistor at the white connector.
- Reference value: 1.10 kohms at 180°C 180 kohms at 10°C