HP LaserJet Enterprise 500 Maintenance Manual - Page 74

replace the shuttle frame assembly.

Page 74 highlights

Chapter 4 Troubleshooting Other Symptoms Table 3. General Symptom List Symptom Solution Horizontal misalignment of characters (Dots or characters move left or right from dot row to dot row or line to line) 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 (that is, all 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 the hammer phasing. Adjust hammer phasing if necessary. 3. If the printer is a a 500 lpm model, check the shuttle speed setting. Set the shuttle speed (page 132). 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. Randomly misplaced dots 1. Power off the printer. Check the platen gap. Adjust the platen gap if necessary. 2. Remove the paper guide assembly or pedestal top cover. On the left rear wall of the card cage, make sure the nut which secures the line filter ground line and the AC In Power Supply cable lead to the ground stud is tight. (See Figure 42, page 226.) 3. Disconnect the AC power cord and check the ground leads for continuity. Replace the AC power cord if it fails continuity test. 4. Make sure the printer is plugged in to a grounded power outlet. Power up the printer. Run a print test. If the problem occurs, replace the hammer bank logic cable. 5. Power up the printer. Run a print test. If the problem occurs, replace the flash memory and DRAM. Download the emulation software again. 6. Power up the printer. Run a print test. If the problem occurs, replace the CMX controller board. 7. Power up the printer. Run a print test. If the problem occurs, replace the power supply board. 8. Power up the printer. Run a print test. If the problem occurs, replace the shuttle frame assembly. 74

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74
Chapter
4
Troubleshooting Other Symptoms
Horizontal misalignment of
characters (Dots or characters
move left or right from dot row to
dot row or line to line)
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
(that is, all 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 the hammer phasing. Adjust hammer phasing if
necessary.
3.
If the printer is a a 500 lpm model, check the shuttle speed
setting. Set the shuttle speed (page 132).
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.
Randomly misplaced dots
1.
Power off the printer. Check the platen gap. Adjust the platen gap
if necessary.
2.
Remove the paper guide assembly or pedestal top cover. On the
left rear wall of the card cage, make sure the nut which secures
the line filter ground line and the AC In Power Supply cable lead
to the ground stud is tight. (See Figure 42, page 226.)
3.
Disconnect the AC power cord and check the ground leads for
continuity. Replace the AC power cord if it fails continuity test.
4.
Make sure the printer is plugged in to a grounded power outlet.
Power up the printer. Run a print test. If the problem occurs,
replace the hammer bank logic cable.
5.
Power up the printer. Run a print test. If the problem occurs,
replace the flash memory and DRAM. Download the emulation
software again.
6.
Power up the printer. Run a print test. If the problem occurs,
replace the CMX controller board.
7.
Power up the printer. Run a print test. If the problem occurs,
replace the power supply board.
8.
Power up the printer. Run a print test. If the problem occurs,
replace the shuttle frame assembly.
Table 3. General Symptom List
Symptom
Solution