Removal; Pinch Roller Mechanism Removal; Paper Drive Shaft And Coupler; Pinch Rollers - HP 7475A Service Manual

Model 7475A
6-77. PINCH ROLLER MECHANISM REMOVAL
6-78. To remove the pinch roller lever and bar or the
right or left pinch roller arm, proceed as follows:
a. Remove the top case. Refer to Top Case Removal.
b. To remove the right pinch roller arm, the pen
drop shield must be removed. See Figure 6-11.
c. Remove the chassis assembly as instructed in
Printed Circuit Assembly Removal, steps b.
throughf.
d. Place the chassis assembly upside down on the
work surface. See Figure 6-19.
e. Remove the pinch roller spring.
f. To remove the pinch roller lever and bar, move
the lever in an upward position and merely slip
out of the chassis.
g. Slide the pinch roller arm from its pivot and
remove from the chassis.
h. Replace all parts in reverse order.
6-79. PAPER DRIVE SHAFT AND COUPLER
REMOVAL
a. Remove the chassis assembly as instructed in
Printed Circuit Assembly Removal, steps a.
throughf.
b. Remove the right and left pinch roller springs
and pinch roller arms.
Section VI
c. Remove both bearing clamps by pressing down
and inward on the clamps. See Figure 6-19.
d. Remove paper drive shaft toward the left.
Do not attempt to replace grit wheels
or bearings individually. The grit wheels
must be press fitted at the factory to
the proper position.
e. Loosen the coupler clamping screw and remove
the coupler from the shaft.
f. When replacing the coupler and drive shaft, place
the coupler on the end of the shaft, leaving the
clamping screw loose enough to allow the coupler
to slide.
g. Place the drive shaft in position, making sure
that the rubber 0-rings on the drive shaft coupler
and the motor shaft coupler fit inside the grooves
of the coupler ring. Replace the bearing clamps.
See Figure 6-12.
h. Place the chassis assembly right side up.
NOTE
Step i. assumes that the paper drive
motor is in position and its clamp
tightened securely. If not, refer to Paper
Drive Motor Assembly.
BEARING CLAMPS
RIGHT
PINCH
ROLLER
ARM
7475-A-27·1
RIGHT
PINCH ROLLER
SPRING
PAPER DRIVE
SHAFT
PINCH ROLLER
LEVER AND BAR
Figure 6-19. Underside of Chassis Assembly
LEFT
PINCH ROLLER
SPRING
LEFT
PINCH
ROLLER
ARM
6-15