Trouble-
shooting
SERVICE CALL CONDITIONS
SM 4-5 B039/B040/B043
No.
Definition
Symptom Possible Cause
Lower paper tray lift motor malfunction (optional two-tray paper tray unit)504 B
The paper lift sensor fails to activate
twice continuously after the tray lift
motor has been on for 18 seconds.
• Paper lift sensor defective
• Tray lift motor defective
• Too much load on the drive
mechanism
• Poor tray lift motor connection
Paper tray motor lock (optional paper tray units)506 B
A motor lock signal is not detected for
more than 1.5 s or the lock signal is not
detected for more than 1.0 s during
rotation.
• Paper tray unit motor defective
• Too much load on the drive
mechanism
Fusing thermostat/thermistor open541 A
The fusing temperature detected by the
thermistor is below 10°C for 5 seconds
after the main power switch is turned
on.
• Fusing thermostat defective or out of
position
• Fusing thermistor defective or out of
position
• Power supply board defective
Fusing temperature warm-up error542 A
The fusing temperature does not reach
80°C within 30 seconds after the main
switch is turned on.
• Fusing thermistor defective or out of
position
• Fusing lamp open
• Fusing thermostat open
• Fusing thermofuse open
• Power supply board defective
Fusing overheat error543 A
A fusing temperature of over 230°C is
detected for 1 second by the fusing
thermistor.
• Fusing thermistor defective
• Power supply board defective
Fusing low temperature error544 A
A fusing temperature of lower than
100°C is detected for 1 second by the
fusing thermistor during operation or
stand-by mode.
• Fusing lamp open
• Fusing thermistor defective
• Power supply board defective
• Fusing thermistor open
• Fusing thermostat open
Unstable fusing temperature546 A
The fusing temperature does not rise
3 °C or more within 5 seconds after the
fusing lamp has been on over 8
seconds.
• Thermistor defective
• Power supply unit defective
Zero cross signal malfunction547 B
Zero cross signals are not detected
within 5 seconds after the main power
switch is turned on, or are not detected
within 1 second after operation begins.
• Power supply board defective
• IOB defective
• BiCU defective
Communication error between IOB and ADF620 B
The IOB does not receive a response
from the ADF main board for 4 seconds
or more.
• Poor connection between the IOB and
ADF main board (DF connector)
• ADF main board defective
• IOB defective
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