Ricoh DD 4450 Service Manual page 215

Service Call Conditions
No.
E-10 Thermal Head Energy Pulse error
The CPU detects an abnormal ID signal from the
thermal head energy control pulse.
E-12 Pressure Plate error
The pressure plate home position sensor signal is not
detected within 6.0 seconds after the pressure plate
motor turn on.
E-13 Scanner error
The scanner HP sensor does not turn on within 15.0
seconds after the main switch turns on.
On the Initial Movement, the Scanner HP sensor does
not turn off when the scanner moves 22.2 mm towards
the scanning position.
On the Initial Movement, the scanner HP sensor does
not turn on within 2.0 seconds after the main switch
turns on.
E-14 SBU Error
SBU errors are most often caused by a SBU element
or lamp that is in poor condition.
E-17 Drum Thermistor Open
The thermistor output voltage is over 2.67 volts.
E-18 Drum Overheat
The temperature of the drum is greater than 54C when
the Start key is pressed.
E-21 Paper Exit Timing Sensor error
The paper exit timing sensor does not activate before
the master eject position sensor activates.
nd
E-22 2 Feed Timing Sensor error
nd
The 2 feed timing sensor does not activate before the
paper exit timing sensor activates.
C279
Symptom
4
Possible cause
Thermal head
connector
Thermal head
MPU
Pressure plate drive
Pressure plate motor
Plate position sensors
Scanner drive
Scanner HP sensor
Scanner motor
SBU
Thermistor connector
Thermistor
Drum overheat
Thermistor
Drum sensors
Feeler
Drum sensors
Feeler
SM Appendix