IBM 6400 series Maintenance Manual page 177

8. The display will show "SERVICE / PRINTER MECHANISM TESTS", the
first menu item. Press Enter to enter the mechanism tests menu.
9. Press Scroll" or Scroll# until
"PRINTER MECHANISM TESTS / END OF FORMS ADJUST" is on the
display.
This test will print a vertical "comb" pattern at around column 70, each
long bar separated by three shorter bars. An enlarged example of the
comb pattern is shown below.
10. Press Enter until the END OF FORMS ADJUST test starts.
The comb pattern will print until the display shows
"001 END OF FORMS / LOAD FORMS" and (if enabled) the audible
alarm sounds. If the alarm sounds, press Stop to silence it.
11. Remove the paper from the tractors and examine the area of the page
perforation. (If the alarm sounds when you open the platen, press Stop
to silence it.)
If a bar from the comb pattern just meets the perforation, the end of
forms adjustment distance is correct. (A bar exactly on perforation is
ideal; 1 or 2 dot rows off is OK; 5 to 7 dot rows off is too much.) Unless
you wish to restart the procedure with 6-part paper, you may stop the test
here, and skip to step 22. (See the note at the beginning of this
procedure.)
If the comb pattern stopped short of the perforation or printed beyond the
perforation, go to step 12.
12. Measure how short or long the comb pattern printed by counting the
number of dot rows needed to reach the perforation, or the number of dot
rows that printed beyond the perforation.
NOTE: You can use the long bars to count the dot rows quickly. There are
Adjustment Procedures
three dot rows between each long bar, so each long bar increases
the number of dot rows by four. You can also tear off a small piece
of the comb pattern from the beginning of the pattern and use it as a
ruler to help you measure the dot rows required either to reach the
perforation or back up to it.
Short Bar
Long Bar
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