KPOWERSCIENCE KP3828 Series, Maintenance Manual

Page: 187 / 230

8-15
Procedure Points to be checked Remedy Checking method
7 Is the KMPU board
normal? If YES, replace the
fuser exit blower.
If NO, replace the
KMPU board.
Disconnect connector CN6 from the
KMPU board, bring the positive lead of
a multimeter in contact with pin 32 of
CN7 and the negative lead in contact
with PG (pin 31), and check the
following 2 points.
Does the voltage become
approximately 0 V when the power is
turned on?
If YES, check the next point.
If NO, replace the KMPU board after
checking the output of the DC power
supply.
Does the voltage become
approximately 5 V at the timing of
printing?
If YES, replace fuser exit blower.
If NO, replace the KMPU board.
8 Is the lamp thermistor
(LTS) normal? If YES, go to 9.
If NO, replace the
LTS.
Let the fuser section cool sufficiently
(to approximately 30
℃
) and then
check the following 2 points.
Bring the positive lead of a digital
multimeter in contact with pin 4 of U37
(LM339MA) of the KMPU board and
the negative lead in contact with SG
(J7), and measure the voltage.
If normal, the voltage will be
approximately 3.7 ± 0.5V.
Remove connection jack J9 from
connector CN9 of the KMPU board,
and measure the resistance across pins
1 and 2 of J9 with a digital multimeter.
If normal, the resistance will be
approximately 22 k ± 3 k
Ω
.
9 Is the KMPU board
normal? If NO, replace 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 check the following 2 points.
Measure the voltage when pins 1 and 2
of CN9 of the KMPU board are not
shorted. If normal, the voltage will be
approximately 0 V.
Also measure the voltage when pins 1
and 2 of CN9 are shorted. If normal,
the voltage will be approximately 5 V.