IBM Selectric Maintenance Manual page 52

b. Carrier Shoe (late) - Adjust the upper carrier shoe
eccentric mounting stud to provide .002" to .006"
vertical motion of the carrier at the rear (Fig. 92)
when the spring load on the upper shoe is suppressed.
CAUTION:
FIGURE
92.
Carrier Shoe - New Style
Eccentric
Stud
Lock-Nut
NOTE: The vertical motion may be felt by firmly
moving the carrier up and down at the rear, so as to
overcome the effects of the spring load on the upper
shoe.
6. Velocity Control Plate - The velocity control plate must
be adjusted to satisfy the following two conditions:
a. With the cam follower held lightly against the low
point of the print cam, the center of the home char-
acter should clear the platen by .260" to .270".
b. With the cam follower held lightly against the high
point of the print cam, the home character should
clear the platen by .020" to .030".
The copy control lever should be forward f~r both ad-
justments. These adjustments shou Id be made with the
carrier at the extreme left hand position.
The adjustments can be made easily if the following pro-
cedure is used.
a. Raise the anvil adjusting eccentrics and the restor-
ing cam follower eccentric to prevent nny inter-
ference, and remove the ribbon feed plate for ac-
cessibility. (Fig.
96).
b. If the velocity control plate is loose or completely
out of adjustment, set the high part of the eccentric
forward and tighten it in place. Adjust the plate so
that about 1/32" of the adjusting slot is visible a-
bove the binding screw and tighten the screw friction
tight. These settings provi de a good starting point.
(Fig. 93).
c. Hand cycle the machine using a zero rotate, zero
tilt character until the print cam follower is on the
high point of the cam. Do not hold the typehead
toward the platen. With the mechanism in this po-
sition, adjust the velocity control plate eccentric
until a slight drag is felt on three tab cards inserted
between the typehead and the platen (Fig. 93). A
heavy drag should be felt on four cards. No drag
should be felt on two cards. You should not be
able to insert five cards.
2-29
Type Head
Held Slightly
Forward
Screw
Control Plate Ecc.
FIGURE 93. Velocity Control Plate
Eccentric Adjustment
This will place the limit of powered travel of the
typenead .020" to .030" away from the platen
(providing the typehead with the proper amount of
free flight).
d. Hand-cycle the machine until the print cam follow-
er is at the low point of the cam. This may not be at
the rest position. The low point of the cam can be
determined by observing the movement of the head
toward the front of the machine. With the type head
at its most forward point, adjust the velocity con-
trol plate pin forward or back in the cam follower
slot until a clearance of .260" to .270" exists be-
tween the center of a zero rotate, zero tilt char-
acter and the platen (Fig.
94).
-_-J
=:::==:::::::~AO\,e
Pin Forward Or Back
FIGURE 94. Velocity Control Plate Adjustment