Xerox Phaser 790, Service Manual

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3-14 Phaser 790/DocuColor 2006
IQ9
Initial Issue Image Quality
IQ9 Deletions RAP
Initial Actions
Reload the machine with fresh, dry paper of the correct specifications. If the problem occurs
when using heavyweight paper, ensure that the correct selections are being made on the print
driver. If the problem is not resolved, continue with this RAP.
NOTE: Small white deletions with a sharp edge are usually caused by Fuser offsetting. Go to
the IQ18 Spots RAP.
Procedure
The problem is debris-centered deletions (small-area deletions surrounding a dark
speck).
Y
N
Enter diagnostic mode (GP 1). Access the Pattern Printing routine. Print a copy of the
20% coverage pattern for all colors. The defect is present for all colors.
Y
N
Replace the Developer Housing (PL 6.2) for the affected color.
Make several prints of the Test Page (GP 14). The defect is present in approximately
the same location on all letter-size prints.
Y
N
The defect is present in the same location on every A3/11 x 17 in. print, or on
every other letter-size print.
Y
N
Rotate the IBT Tension Lever back and forth as you examine the IBT Belt.
There is clearance between the Push In Shaft (PL 7.2) and IBT Belt when
the Tension Lever is in the locked position.
Y
N
Repair or replace the IBT Assembly (PL 7.2).
Reinstall the Copy/Print Cartridge. Connect the DVM between the D terminal
on the HVPS and frame ground. Access the Digital Output Test (GP 2). Enter
code 0B. Press the Item/Enter button. R80 VDC is measured.
Y
N
Go to the IQ6 RAP to troubleshoot the BTR 1 bias circuits.
Replace the IBT Belt (PL 7.2).
Replace the IBT Belt (PL 7.2).
Access the Digital Output Test (GP 2). Enter code 71. Press the Item/Enter button.
Remove the Copy/Print Cartridge. The Erase lamp is lit.
Y
N
There is +5 VDC from pin 2 to pin 1 on J 86.
Y
N
There is + 5 VDC from J 86 pin 2 to frame ground.
Y
N
Go to Flag 1. Check for an open circuit. If the wire is OK, replace the MCU
PWB (PL 11.2).
Go to Flag 2. Check for an open circuit. If the wire is OK, replace the MCU PWB
(PL 11.2).
Replace the Erase Lamp (PL 5.1).
Examine the surface of the photoreceptor drum in the Copy/Print Cartridge. Check for
dents, scratches, or contamination such as fingerprints, etc. The drum is clean and free
from damage.
Y
N
Clean or replace the Copy/Print Cartridge (PL 5.1) as required.
Remove the ROS. Examine the ROS window for dirt or damage. Clean or replace as
required.
If the problem remains, replace the Copy/Print Cartridge (PL 5.1). If this does not resolve
the problem, replace the ROS (PL 5.1).
Examine the spot in the center of the DCD. Check the Developer spacing (ADJ 9.1) for the
affected color. If the check is OK, replace the Developer Housing (PL 6.2) and Dry Ink Car-
tridge for the affected color.
A
A
B
B
C
C
D
D