2KT/2KV
1-4-26
7404 Developing unit Y non-
installing error
No density detection signal is
output from toner sensor Y in
developing unit Y.
Defective connec-
tor cable or poor
contact in the con-
nector.
Reinsert the connector. Also check for conti-
nuity within the connector cable. If none,
replace the cable.
Developing unit Y and Drum relay PWB
(YC13)
Drum relay PWB (YC1) and engine PWB
(YC34)
Defective toner
sensor Y.
Replace the developing unit Y (see page 1-
5-18).
Defective engine
PWB.
Replace the engine PWB and check for cor-
rect operation (see page 1-5-26).
7411 Drum unit K non- installing
error
The EEPROM of drum PWB K
does not communicate nor-
mally.
Installation of
incompatible drum
unit K.
Install drum unit K compatible with the spec-
ifications to the machine.
Defective connec-
tor cable or poor
contact in the con-
nector.
Reinsert the connector. Also check for conti-
nuity within the connector cable. If none,
replace the cable.
Drum unit K and Drum relay PWB (YC2)
Drum relay PWB (YC1) and engine PWB
(YC34)
Defective drum
PWB K.
Replace the drum unit K (see page 1-5-20).
Defective engine
PWB.
Replace the engine PWB and check for cor-
rect operation (see page 1-5-26).
7412 Drum unit C non- installing
error
The EEPROM of drum PWB
C does not communicate nor-
mally.
Installation of
incompatible drum
unit C.
Install drum unit C compatible with the spec-
ifications to the machine.
Defective connec-
tor cable or poor
contact in the con-
nector.
Reinsert the connector. Also check for conti-
nuity within the connector cable. If none,
replace the cable.
Drum unit C and Drum relay PWB (YC4)
Drum relay PWB (YC1) and engine PWB
(YC34)
Defective drum
PWB C.
Replace the drum unit C (see page 1-5-20).
Defective engine
PWB.
Replace the engine PWB and check for cor-
rect operation (see page 1-5-26).
Code Contents Causes
Check procedures/
corrective measures