2RV/2RW/2RX/2RY/3RA-3
7-88
C7220: Broken in-machine thermistor
The in-machine thermistor input sampling value exceeds the reference value.
C7800: Outer thermistor broken
The temperature/humidity sensor (external thermistor) input sampling value exceeds the reference value.
C7990: Waste toner full
The waste toner sensor detected the waste toner box in the drum unit full.
4 Replacing the main/engine
PWB
The main/engine PWB is
faulty.
Replace the main/engine
PWB.
Step Check description Assumed cause Measures Reference
1 Checking the connection The connector is not prop-
erly connected or the wire
is faulty.
Clean the terminal of the fol-
lowing wire connectors and
reconnect the connectors. If
there is no continuity, replace
the wire.
• In-machine temperature
sensor - Main/engine PWB
(YC1)
2 Replacing thein-machine
temperature sensor
The in-machine tempera-
ture sensor is faulty.
Replace the in-machine tem-
perature sensor.
3 Replacing the main/engine
PWB
The main/engine PWB is
faulty.
Replace the main/engine
PWB.
Step Check description Assumed cause Measures Reference
1 Checking the connection The connector is not prop-
erly connected or the wire
is faulty.
Clean the terminal of the fol-
lowing wire connectors and
reconnect the connectors. If
there is no continuity, replace
the wire.
• Temperature/humidity sen-
sor - Main/engine PWB (YC2)
2 Replacing the tempera-
ture/humidity sensor
Temperature/humidity sen-
sor is faulty.
Replace the temperature/
humidity sensor.
3 Replacing the main/engine
PWB
The main/engine PWB is
faulty.
Replace the main/engine
PWB.
Step Check description Assumed cause Measures Reference
1 Replacing the drum unit The waste toner reservoir
in the drum unit is full.
Replace the drum unit if not
recovered after turning the
power off and on.
Step Check description Assumed cause Measures Reference