IBM 6400 series Maintenance Manual page 71

2. Press Form Feed several times and check that forms feed without erratic motion,
noise, or pin-hole damage.
If forms do not feed, go to Paper feeds poorly, page 121.
If forms feed, go to step 3.
3. Press View once and check that forms move up.
Make sure the forms thickness lever is not set too tightly.
4. Press View again and check that the forms thickness lever rotates and the paper
moves down.
If the forms thickness lever does not rotate and/or the paper does not
move down, refer to Reverse paper feed: platen does not open, page
124.
5. Check the paper tension between the tractors.
Adjust the right tractor so that it does not pull paper too tightly or leave it
too loose. The right tractor should hold the paper under "slight" tension.
6. Inspect the ribbon mask for bends or deformation that block the paper path or
prevent paper from exiting the pedestal top cover.
Replace a damaged hammer bank cover assembly.
7. Check the condition and tension of the platen open belt.
Adjust the platen open belt. Replace the belt if it is damaged.
8. Check the platen open pulley and the platen pulley for looseness.
Bottom out the platen open motor pulley on the motor shaft and torque
the 1/16 inch set screw to 9
the 7/64 inch setscrew in the platen shaft pulley, then open and close the
forms thickness lever and check that the platen pulley setscrew does not
hit the left ribbon guide.
9. Inspect the tractors and tractor door springs for damage or excessive wear.
If either tractor is worn or damaged, replace both tractor assemblies.
10. Check the condition and tension of the paper feed belt.
Adjust the paper feed belt. Replace the belt if it is damaged.
11. Check the platen gap.
Adjust the platen gap.
Troubleshooting
2 inch-pounds (1.02 0.23 N m). Tighten
71