IBM 3112, Service Manual

Page: 47 / 184

bh1s.bk : bh1sdiag.doc 31 Thu Apr 20 12:42:16 1995
Diagnostic Information
31
Spacings other than the ones listed could be caused by damage or a
bind in the gear train.
Residual Image
Residual image--the “walking” of a leftover image down the page--is
probably the result of failed erase lamps not discharging the photocon-
ductor, or of a failed cleaner inside the print cartridge. It can also be
caused by a failed fuser hot roll retaining toner and redepositing it on
the page. Check that the erase lamp voltage at engine board J9-1 is
+24VDC and that the cable has continuity.
To test the erase lamps, jumper engine board J9-2 to ground.
Random Marks
Random marks are nearly always due to a mechanical problem or due
to foreign matter loose in the printer or in the print cartridge. Inspect and
clean the inside of the printer carefully and correct any problems found.
Skew, all edges
If the test print frame is parallel to all edges of the page but the margins
are not all the same width.
See
“Print Registration” on page 47.
Component Print Defect Spacing on Page
PC Drum (part of print cartridge) 125.7 mm
Transfer Roll 53.1 mm
Fuser Hot Roll 78.9-79.2 mm
Fuser Backup Roll 69.1 mm
Charge Roll (part of print cartridge) 37.1-37.7 mm
Developer Roll (part of print cartridge) 40.0mm
Prealigner Feed Roller 68.5 mm
Auxiliary Feed Roller 68.5 mm