Ricoh FT4430 Service Manual page 102

16 April '88
SERVICE CALL CONDITIONS
Self-diagnostic Code 53:
Thermistor Open
The main CPU checks the conductivity of the thermistor. Code 53 is displayed
if the thermistor circuit is open.
Self-diagnostic Code 54:
S _
No Warm-up ignal
Code 54 is displayed if the hot roller does not reach the ready temperature
within 8 minutes after the power is turned on.
Self-diagnostic Code 55:
Overheat
The main CPU checks the conductivity of the thermistor. Code 55 is displayed
if the resistance of the thermistor becomes too low. This occurs if the hot
roller temperature is in the 200°- 240"C range.
Self-diagnostic Code 56:
Temperature Too Low
Code 56 is displayed if the CPU detects that the temperature of the hot roller
is less than 150°C after the CPU detects the ready signal.
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