KPOWERSCIENCE KP3828 Series, Maintenance Manual

Page: 186 / 230

8-14
[20 Fuser unit overheat (Lamp housing)]
Procedure Points to be checked Remedy Checking method
1 Is the KMPU board
normal? If YES, go to 2.
If NO, go to 5.
Bring the positive lead of a digital
multimeter in contact with pin 2 of U37
(LM339MA) of the KMPU board, and
the negative lead in contact with SG
(J7), and then check whether or not the
voltage is approximately 0 V (Normal
if yes).
2 Is the fuser unit set
properly? If YES, go to 3.
If NO, set the fuser
unit properly.
3 Is the lamp temperature
fuse (LTF) normal? If YES, go to 4.
If NO, replace the
LTF.
Remove connection jack J9 from
connector CN9 of the KMPU board.
Measure the resistance across pins 3
and 4 of J9 with a digital multimeter.
If normal, the resistance will be
approximately 0
Ω
.
4 Is the KMPU board
normal? If YES, go to 5.
If NO, follow the
instructions to the
right.
Check as follows
：
Short pins 3 and pin 4 of connector
CN9 of the KMPU board.
Bring the positive lead of a digital
multimeter in contact with pin 2 of U37
(LM339MA) of the KMPU board and
the negative lead in contact with SG
(J7), and measure the voltage. Is the
voltage approximately 5 V (normal)?
If YES, go to 5.
If NO, go to 9.
5 Is the temperature
abnormally high (80
℃
or higher)?
If NO, go to 8.
If YES, cool the
fuser unit.
6 Is the fuser exit blower
normal? If YES, go to 8.
If NO, go to 7.
Fuser exit blower is normal if it is
rotating during the cooling of the fuser
unit and during the printing operation.
-To be continued-