IBM 6400 series Maintenance Manual page 132

Vertical misalignment of characters:
1. Dots or characters move up or down from dot row to dot row or line to line
2. Incorrect spacing from dot row to dot row or line to line
3. Characters randomly compressed and/or enlarged
1. Load paper. Press Form Feed and check that paper feeds smoothly. Press View
to verify that paper moves in both directions. Check the forms thickness lever: if it
is set too loose or too tightly print quality can be affected.
Set the forms thickness lever to match the thickness of the paper being
used.
2. Check the paper feed motor pulley for looseness.
Hold the collar snug against the motor pulley and torque the 7/64 inch
setscrew to 25
3. Check the condition and tension of the paper feed timing belt.
Adjust the paper feed timing belt. Replace the belt if it is damaged.
4. Check the platen gap.
Adjust the platen gap.
5. Inspect the tractors and tractor door springs for damage or excessive wear.
If either tractor is damaged or excessively worn, replace both tractor
assemblies.
6. Remove the paper guide assembly or pedestal top cover. Make sure connector
P107/PAPR M is fully seated in connector J107 on the CMX controller board.
Connect P107/PAPR M to J107 on the CMX controller board.
7. Power on the printer. Load paper. Run a print test.
If the problem occurs, replace the paper feed motor.
8. Run a print test.
If the problem occurs, replace the CMX controller board.
9. Run a print test.
If the problem occurs, replace the power supply board.
132
2 inch-pounds (2.82 0.23 N m).
Troubleshooting