Possible cause
Step
Development
10
input signal error
Dirt on power
11
supply terminal
Failure in the
development
high-voltage
circuit
Dark
I-2
Possible cause
Step
Density setting
1
EP-ED cartridge
2
Dirt on the
3
grounding
terminal
Charging input
4
signal error
Dirt on power
5
supply terminal
Failure in the
charging high-
voltage circuit
Check
Do the pins 3, 4 and 5 of the connector
P6 on the main PCB have the following value
respectively when a sheet of paper is fed from
the MP tray?
P6-3 pin (DBAC) --- Change in voltage from
6V approx. to 0V just when a sheet of paper is
fed from the registration unit.
P6-4 pin (DBDC) --- Change in voltage from
9V approx. to 0V just when a sheet of paper is
fed from the registration unit.
P6-5 pin (DNSTY) --- Change in voltage to
2.5V just when a sheet of paper is fed.
Is there any dirt on the cartridge side
development terminal of the transfer unit and
on the terminal of the high-voltage power
supply development unit? (is there continuity
between them?)
Check
Does printed image improve when density
setting is changed on the control panel?
Does printed image improve when the EP-ED
cartridge is replaced?
Does printed image improve when continuity
is improved by cleaning the EP-ED cartridge
grounding terminal and the printer unit
grounding terminal?
Do the pins 1, 2 and 5 of the connector P6
on the main PCB have the following value
respectively when a sheet of paper is fed from
the MP tray?
P6-1 pin (HV1AC) --- Change in voltage from
6V approx. to 0V just when a sheet of paper is fed.
P6-2 pin (HV1DC) --- Change in voltage from
9V approx. to 0V just when a sheet of paper is fed.
P6-5 pin (DNSTY) --- Change in voltage to
2.5V just when a sheet of paper is fed.
Is there any dirt on the cartridge side charging
terminal of the transfer unit and on the terminal
of the high-voltage power supply charging unit?
(is there continuity between them?)
Result
No
No
Yes
Result
Yes
Yes
Yes
No
No
Yes
VI - 5
Remedy
Replace the scanner unit or
the harness.
Clean the contacts to assure
the continuity.
Replace the high-voltage
power supply PCB assy.
Remedy
Adjust the proper setting on
the control panel.
Replace the EP-ED cartridge.
Clean the contacts to assure
the continuity.
Replace the main PCB assy
or the harness.
Clean the terminal to assure
the continuity.
Replace the high-voltage
power supply PCB assy.