NCR 7156, Руководство по эксплуатации и устранению неисправностей

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18 Chapter 2: Troubleshooting
The read head must maintain a line of total contact with the black foam
pad on the print head carriage. To examine the line of contact, remove
the cantilever assembly with the read head attached. For more
information, see the 7156 Service Guide. Remove the ribbon cassette and
move the print head carriage to 1 inch from the right end of carriage
travel. Depress the MICR solenoid plunger all the way down; the read
head presses against the foam pad on the print head carriage. From the
front of the cantilever, examine the line of contact between the read
head and the foam pad. There should not be a gap at any point along
the top of the read head as shown in the illustration above.
If a gap exists, loosen the read head bracket mounting screw, twist the
bracket assembly to remove the tilt and tighten the mounting screw.
Reassemble the printer and perform the MICR adjustment. Then repeat
the MICR read test. For more information on adjusting the MICR, see
“In-Place MICR Adjustment” on page 20.
Improper Document Motion
An unacceptable MICR read rate or a failure rate greater than 1% may
indicate a damaged or obstructed document, bumps on the paper feed
rolls, or a platen gap that is too tight.
Check each of the following in turn to determine the cause of the
problem.
Damaged or Obstructed Document
Check the document for surface bumps or damage. The document
should remain flat and unobstructed during the MICR read. Check
both sides of the document for:
•
Taped patches. If there are patches or other surface discontinuities,
do not use the document for test purposes.
•
Sharp creases caused by folding: MICR reading errors can be
reduced by flattening the creases, but don’t use the document for
testing.