Ricoh DD 4450 Service Manual page 216

No.
E-23 Master Eject Position Sensor (Drum HP) error
The master eject position sensor does not activate
before the feed start timing sensor activates.
E-24 Feed Start Timing Sensor error
The feed start timing sensor does not activate before
the 2nd feed timing sensor activates.
E-40 Thermal Head ID error
The CPU detects an abnormal ID signal from the
thermal head.
E-41 Ink Idling roller HP sensor remains on or off
The idling roller HP sensor does not change status
within 4.0 seconds after the idling roller motor on signal
is generated.
E-42 Duct plate error
The duct plate HP sensor does not change status
within 4.0 seconds after the duct plate motor on signal
is generated.
E-43 Printing Pressure error
The printing pressure HP sensor does not change
status within 4.0 seconds after the printing pressure
motor on signal is generated.
E-44 MSU error
When error signal is received from the MPU board.
E-47 Thermal head driving error
The thermal head HP sensor does not change status
within 4.0 seconds after the thermal head driving motor
on signal is generated.
E-50 Insufficient NVRAM data
The data in the NVRAM is not the expected data for
this machine (version update error)
SM Appendix
Symptom
5
Service Call Conditions
Possible cause
Drum sensors
Feeler
Drum sensors
Feeler
Thermal head
MPU
Thermal head
connector disconnected
Idling roller HP sensor
Ink idling motor
Duct plate HP sensor
Duct plate motor
Printing pressure HP
sensor
Printing pressure motor
MPU
Thermal head HP
sensor
Thermal head driving
motor
NVRAM (MPU)
C279