IBM 6400 Maintenance Information Manual page 122

Chapter 5
Troubleshooting Other Symptoms
Symptom
Characters or dots are
missing, smeared, too
light, or too dark
(continued)
Horizontal misalignment
of characters (Dots or
characters move left or
right from dot row to dot
row or line to line)
122
Table 5. General Symptom List
Corrective Action
13. Power on the printer. If the problem still occurs, replace the
power supply board.
14. Power on the printer. If the problem still occurs, replace the CMX
controller board.
1. Take the printer offline and print a test pattern of All H's. If
characters shift left or right from line to line, there might be a
proportional spacing problem. If the pattern of H's prints
correctly (i.e., the columns line up), contact your support group
or configuration help desk, because a configuration change may
be necessary. If the pattern of H's did not print OK, go to the
next step.
2. Check and adjust hammer phasing.
3. If the printer is a model 6400-004, -04P, -005, or -05P, check the
shuttle speed setting (page 182).
4. Inspect the shuttle frame assembly area for ink residue, paper
chaff, or debris. Clean the shuttle frame assembly.
5. Check the MPU gap. Using a feeler gauge, adjust the gap
between the MPU assembly and the flywheel to 0.010 ± .001
inch (0.254 ± 0.025 mm). Torque the
7/16 inch MPU clamp screw to 18 ± 1 inch-pounds (2.03 ± 0.11
N•m).
6. Power up the printer. Run a print test. If the symptom is not
gone, replace the MPU.
7. Power up the printer. Run a print test. If the symptom is not
gone, replace the CMX controller board.
8. Power up the printer. Run a print test. If the symptom is not
gone, replace the shuttle frame assembly.