Sporadic Form Feeding and repetitive character printing
ATTN: FIELD
SERVICE
SUBJECT: 850XL Sporadic Form Feeding and repetitive character
printing
PRODUCT: 850XL and 560DL
ORIGINATOR: Terry Madnick
DATE: 02/29/01
REVISED: 12/07/2000
TECH BULLETIN #: 99-850-002
REVISED: 02/29/01
PROBLEM/SYMPTOM:
Some 850XL and 560DL's will print repetitive characters,
or exhibit uncontrolled form feeding after putting the printer
back online after a formfeed has been performed.
CAUSE:
Improper grounding from the print mechanism to the baseplate
of the printer. This problem believed to be noise susceptibility
problem on BSYSET* line driven by 74LS259 latch.
SOLUTION/PROCEDURE:
A ground-strap from the carriage mechanism
shock mount screw to the baseplate of the printer
and installing the shielded linefeed cable will resolve
this issue. Unplug the printer. After removing the screws
to the enclosure, remove the keypad cable and enclosure.
Locate the carriage motor on the left rear side of the printer.
As noted in the following pictures, install the ground-strap
with star washer underneath strap as shown, using screws
A and B.
Replace existing linefeed motor cable with the shielded cable.
Install version 1.04 firmware in socket U19 . Reinstall the
keypad cable and enclosure.
SUMMARY:
Part Number 0200000740 ground-strap, 0724300000 star-washer
and 0200019000 Linefeed motor cable is required for this
procedure. FirmwareVersion 1.04B
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