TROUBLESHOOTING GUIDE
SM 4-21 G104
Trouble-
shooting
4.3 TROUBLESHOOTING GUIDE
NOTE: When replacing the engine control board, remove the NVRAM from the
original engine control board and install it on the new one.
SYMPTOM
4.3.1 BLANK PRINT
Symptom Possible cause Necessary actions
Defective LDU Replace the LDU.
Defective PCU Replace the PCU.
Defective transfer belt unit
Replace the transfer belt
unit.
Incorrect action of transfer
roller
Check the guide and the
transfer roller.
Defective high voltage
supply board
Replace high voltage supply
board 1 or 2.
No image is printed.
Defective engine board
(EGB)
Replace the engine board
(EGB).
4.3.2 ALL-BLACK PRINT
Symptom Possible cause Necessary actions
Incorrectly installed PCU Install the PCU correctly.
Defective PCU Replace the PCU.
Defective high voltage supply
board
Replace high voltage supply
board 1 or 2.
Defective LDU Replace the LDU.
Defective engine board
(EGB)
Replace the engine board
(EGB).
All the paper is black.
Defective main board Replace the main board.