Xerox 3050 Service Manual page 364

CQ 27 Exposure Control RAP
(1 1/02/92)
This RAP is used i f the photoreceptor
background voltage cannot be set in ADJ 9.2,
Uniform Background, BandingIStreaks,
Light Copy, and Poor Resolution.
Initial Actions
0
Ensure that connectors A2 P208, A3
P304, A4 P21, A4 P22 are
connectedheated properly.
Ensure that the exposure lamp and
the Jacket is positioned properly.
Procedure
he exposure lamp, charge, developer
bias, erase lamp, main drive, fuser, and
the drum cleaning blade are active when
diagnostic code 1092 1-51 is entered.
Enter the diagnostic code [0921-51. Note the
lllumination sensor voltage on the message
display. Press copy contrast down button 3
times.
The illumination sensor voltage decreases by
greater than 2.0 VDC.
The illumination sensor voltage changed
by less than 2.0 VDC, but more than zero
change.
N
Press stop and enter [0921-51. While
observing the lamp intensity press
the copy contrast down button 3
times.
The lamp intensity decreased.
Y N
A B C D
A B C
Press stop and connect the DMM
between A2 P208 pin 7 and
ground. Enter [O921-5] and note
the illumination Bias voltage on
the top line of the message
display. Press copy contrast
down button 3 times.
The Bias voltage and DMM
voltage both decreased by at
least 7.0 VDC.
Y N
Go t o Flag 2 and check the
wiring for a short circuit. If
the problem
still
exists,
replace the LVPS. If the
problem still exists, replace
the Controller PWB.
Replace the Lamp Ballast PWB. If
the problem is still present go t o
Flag 3 and check the wiring for a
short circuit. If the problem still
exists, replace the Exposure Lamp
Go to Flag 1 and check the wiring for
an open or short circuit. If the
problem still exists, replace the
lllumination sensor. If the problem
still exists, replace the Controller
PWB.
Press stop and connect the DMM
between A2 P208 pin 7 and ground.
Enter [0921-51 and note the illumination
Bias voltage on the top line of the
message display. Press copy contrast
down button 3 times.
The Bias voltage and DMM voltage both
decreased by at least 7.0 VDC.
Y N
I
Go t o Flag 2 and check the wiring for
a short circuit. If the problem still
exists, replace the LVPS. If the
problem still exists, replace the
Controller PWB.
Press stop and connect the DMM
(-)
lead
t o A3 P3O4 pin 16 and the (
+
) lead to pin
17. Enter [O92 1-51 and press the copy
contrast down button
3
times.
The DMM voltage increased by more
than 2.0 VDC.
N
Go t o Flag 1 and check the wiring for
an open or short circuit. If the
problem still exists, replace the
lllumination sensor. If the problem
still exists, replace the Lamp Ballast
PWB. If the problem is still present
go t o Flag 3 and check the wiring for
a short circuit. If the problem still
exists, replace the Exposure Lamp. If
the problem still exists, replace the
Controller PWB.
Redace the Controller PWB.
Press
stbp
then press start and enter [OW
1-51.
The illumination sensor voltage on the
message display is at least 3.3 VDC.
Y N
I Check for a physical light blockage of the
lllumination sensor. The illumination
sensor voltage on the message display is
at least 3.3 VDC.
Y N
I
I
Return to pathC.
I
Return to the
RAP
that directed you
here.
Return to the RAP that directed you here.
CQ 27 Exposure Control RAP