IBM 6400 series Maintenance Manual page 126

2. Check that the ribbon spools are not rubbing against the shuttle cover assembly.
Install the shuttle cover assembly correctly, so that the ribbon spools do
not rub against it.
3. Inspect the paper print path for paper chaff, ink residue, and debris.
Clean the shuttle frame assembly.
4. Power on the printer. Run a print test and observe ribbon movement across the
left and right ribbon guides.
Adjust the right and left ribbon guides.
5. Observe ribbon movement at both left and right ribbon posts as the metal end
strip crosses each ribbon post.
If the metal strip moves past either post without reversing the direction of
the ribbon, power down the printer. Remove the paper guide assembly or
pedestal top cover. Reseat connectors P106/LRP and P107/RRP on the
CMX controller board.
6. While shorting across each ribbon post with the ribbon metal strip or a
screwdriver, check for continuity in connector P106/LRP pins 10 and 12, and
connector P107/RRP pins 14 and 16. (Refer to the Main Wire Harness Test
Tables on page 297.)
Replace a ribbon post that fails the continuity test.
7. Check the platen gap.
Adjust the platen gap.
Shuttle does not move
1. Power down the printer. Remove the shuttle cover. Check the MPU gap.
Adjust the gap between the MPU assembly and the flywheel to 0.010
.001 inch (0.254
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2. Check that the MPU cable is connected to J03 on the mechanism base. Check
that the shuttle motor cable is connected to J02 on the mechanism base.
Connect the MPU and the shuttle motor cables.
3. Remove the paper guide assembly or pedestal top cover. Check that the shuttle
motor drive cable is connected to J116 on the CMX controller board.
Connect the shuttle motor drive cable.
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0.025 mm). Torque the 7/16 inch MPU clamp screw to
1 inch-pounds (2.03 0.11 N m).
Troubleshooting