IBM 6400 Maintenance Information Manual page 117

Symptom
Stacker chatters at
upper or lower limit
Table 5. General Symptom List
1. Check for and remove obstructions preventing elevator
movement.
2. Check for misaligned stacker rails Adjust the stacker rails if they
are not vertical and parallel.
3. Move the elevator up and down by hand. Check that the limit
switches are tripped when elevator reaches top and bottom of
travel. If necessary, gently bend contact arms to adjust limit
switches. If you cannot adjust a switch that requires adjustment,
replace it.
4. Power on the printer. Operate the power stacker. (Refer to the
Operator's Guide.)
While the stacker is operating, check that:
a) all motors are operating
b) the paddles are rotating
c) the elevator moves smoothly and without obstruction
d) the timing belts are undamaged and the belt pulleys are not
slipping
e) the extension springs are attached and undamaged (not bent
or stretched)
f) the drive rollers are not damaged
g) the constant force springs are tightly mounted and
undamaged
Tighten pulley setscrews and/or replace damaged components
as necessary.
General Symptom List
Corrective Action
117