IBM Selectric Maintenance Manual page 38

9. Detent Cam Follower Bracket - Position the detent cam
follower bracket which is mounted to the left side of the
carrier by two screws to satisfy the following conditions:
a. Front to rear for a clearance of .015" between the
print sleeve and the end of the pin on the cam fol-
lower (Fig. 54A).
Cern Follower Pin
Detent Cam Follower
Bracket
FIGURE 54A. Detent Cam Follower Bracket
b. Vertically so that the bottom surface of the pin on
the cam follower lines up with the scribe line #1 on
the Hooverometer when the Hooverometer is placed
against the print sleeve as shown in Figure 54B.
This bracket is set at the factory with a dial indicator and
should not require readjustment unless it becomes loose.
c...._-
Hooverometer
Detent Cam Follower Bracket
FIGURE 54B. Detent Cam Follower Bracket
NOTE: The position of the bracket directly affects the tim-
ing relationship between the detent cam and the print cam.
An improperly adjusted bracket may cause the detents to be-
gin to withdraw before the typehead prints, or the typehead
to print before the detents have fully seated. If this occurs
it will generally show up as poor vertical alignment because
the tilt detent always seats after and withdraws ahead of the
rotate detent.
2-15
10. Detent Mechanism (Machines prior to gearless ti It) -
The detent mechanism must be adjusted to satisfy the
following conditions:
a. Position the ribbon feed and detent cam left or
right on the print sleeve so that the insi de rib of
the cam wi II be in line with the left hand edge of
the ribbon feed cam follower (Fig. 55).
Ribbon Feed and Detent Cam
These Two Cam Follower
Edges Even
FI GURE 55. Ribbon Feed Cam
b. Adjust the detent actuating lever support front or
rear (under its locking screw) so that the rotate
detent will c lear the teeth on the typehead ski rt by
.025 to .035" when the cycle shaft is at rest (Fig.
56). This clearance should be observed when the
typehead is manually tilted to a two tilt position
since the two tilt position provides the rotate detent
with the least amount of motion.
FIGURE 56. Skirt Clearance
Moving the actuating lever support to the rear wi II
increase skirt clearance.
c. With the detent cam follower on the low dwe II of
the detent cam (detents fu II y seated) rotate the
actuating lever support until .001" clearance is
felt between the detent actuating lever and the de-
tent cam follower roller. Rotating the support
clockwise will increase the clearance.
NOTE: The adjustments of the detent mechanism directly
affect each other and must be adjusted alternately to obtain
the correct clearances.
The .001" clearance adjusted into the system between
the detent actuating lever and the detent cam follower
insures that the tilt detent will fully seat in the detent
notch of the tilt ring. Too much clearance would allow
the detents to enter their notches too early and withdraw
too late. This could cause an intermittent erroneous
character to print, parts breakage, or roHer droppage in
wear compensator.