Xerox 8830 Service Manual page 272

TRANSFER AND DEVELOPER BIAS
VOLTAGES ARE INCORRECT TAG
19)
PROBLEM
Transfer and developer voltages are set
incorrectly.
CAUSE
Late in the program it was determined that the
developer bias should be set at -420 VDC and
transfer should be set at .6 ma DC .
Inadvertently the change was never cut in on
the manufacturing line. The current settings
can cause intermittent broken black lines or
background bands in the process direction.
SOLUTION
PLEASE MAKE THE
ADJUSTMENT CHANGES TO THE 8830 ON
THE NEXT SERVICE CALL!
1. ADJUST the Transfer output to "+ 0.6
VDC"
Refer to section 6 of manual; GP1 HVPS
Checkout Locate the
potentiometer ("TRF I") nearest the center
of the HVPS (closest to the transfer output
transformer module). Carefully remove
the RTV. Using the 26V return on the
HVPS as the common and the "TFR I"
test point, adjust the potentiometer to
obtain "+ 0.6 +/- 0.1 VDC" during a print.
Mark appropriate change in manual (Table 1
on page 6-10).
Service Notes
CHANGE the Developer Bias default
Enter diagnostic mode - General Procedures
section 6 of manual.
code
ENTER
1E (E is obtained by holding down the period(.)
button and
ENTER
Message: chain 84; address 01E is 4E. Using
the "Previous Button" scroll down six (6) times
or until the display reads chain 84; address
01E is 48.
ENTER
EXIT
EXAMINE Developer bias output level -
Refer to section 6 of manual; GP1 HVPS
Checkout. Using the 26V return on the HVPS
FOLLOWING as the common and the "DEV V" test point.
In the print mode the output should be "(-)
4.20 +/- 0.05 VDC". Mark appropriate change
in manual (Table 1 _on page 6-10).
Mark off TAG 19 on the tag matrix
Once these adjustments are. made you may
Transfer
see a slight increase in toner consumption.
The benefits of doing these adjustments are:
•
Input diagnostic test
84.
striking the "4" button).
Increase "Cleaning Field" latitude
• Reduced occurrence of
background bands in the
process direction.
• Reduced occurrence of
intermittent broken black
lines in the process
direction.
Provides additional lubrication for
the cleaning blade.
1/98
6-38
CAUTION: The tolerance window for
-
electrostatics on the 8830 is very narrow.
This printer must be set to specifications using
the electrometer to
performance. If electrostatics
incorrectly the 8830 will exhibit print quality,
excessive dirt levels, and increased toner
consumption.
REQUIREMENTS FOR FIELD RESOLUTION
. DOCUMENTATION
N/A
• TAG
19
• PART NUMBERS
N/A
• CUT IN SERIAL NUMBER
N/A
ensure proper
are set
8830