IBM Selectric Manual

CAUTION: Be sure that the cam is latched at rest when
the clearance adjustments are observed.
NOTE: The clearances may be observed by pulling the
latches to the rear with a spring hook whi Ie the machine
is at rest.
4. ~nte.rposer Adjusting Screws - Adjust the interposer ad-
pJSfiiig SCi~·;:S so that a frciit to rc-'" ,..II." ...... _.,.,,~'O ",f """"
to .015" exists between all the o~r~;i~~~i'l~t~i,~s~~~d
5.
their respective cam followers (Fig. 107).
Cam Follower
Make Adjustment Here
Interposer
FIGURE 107. Interposer Adjusting Screw
The adjustment directly affects the timing between the
cam release and the positioning ofthe operational latches
under the cam follower. Excessive clearance can allow
the cam follower to move down at the rear before the
latch has moved fully under the follower.
The adjustment may be checked after operating the cams
enough to move the cam followers down sl ightly at the
rear. With the machine on its back the latches can be
pushed
against the cam followers to estimate the clear-
ance.
All ofthe operational interposer springs should be placed
in the middle hole at the rear of the interposer except
the spacebar interposer spring which should be placed in
the lower hole.
NOTE: The keylever pawl to interposer clearance should
be rechecked after this adjustment.
Cam Check Ring - Adjust the cam check ring eccentric
(Fig. 108a) so that a clearance of .010" to .015" exists
between the tipofthe cam pawl an<i the teeth of the cam
ratchet with the cam latched in the rest position (Fig.
1 08 b) • Keeptlfe high part of ,the eccentric radially out-
ward. The check ring mounting screws must be loosened
before the adjustment can be made.
The.adjustment insures that the pawl will clear the rat-
chetand that the check ring will latch positively at the
completion of each cam operation.
40
Adjust Eccentric
Cam Check Ring
A. LEFT SIDE OF CAM
Cam Pawl
B. RIGHT SIDE OF CAM
FIGURE 108. Cam Check Ring Adjustment
6. Clutch Release Arm Stops - Form the adjustable stop lugs
on the operational control bracket to control the amount
of bite that each clutch release arm will take on its re-
spective clutch wheel. This adjustment is observed by
measuring the amount of clearance that exists between
the stop lugs and the lower extension of each clutch re-
lease arm (when the release arm has released the clutch
wheel and is resting against the high portion of the tooth
on the clutch wheel). (Fig. 109). This clearance should
be
.030" to .040".
7.
Make certain that the interposers are latched forward
and are not in contact with the clutch release arms when
observing this ad justment.
NOTE: On long carriage machines the operational
clutch ratchet must be positioned laterally on the opera-
tional shaft so that each clutch release arm will take an
equal lateral bite on its respective clutch wheel. This
insures
that neither clutch release arm can slip side-
ways off itsrespective clutch wheel causing an unwanted
cam operation. This condition is most serious on the car-
rier return/index cam as it wi" cause an index opera-
tion to occur each time the cam is released.
Clutch Re lease Arms - Form the lug at the bottom of each
clutch release arm so that it clears the interposer lugs
by
.030" to .040" (Fig. 110). The interposers and cams
must be
latched when the adjustment is observed.

IBM Selectric Specifications

General

Type	Electric typewriter
Introduced	1961
Keyboard Layout	QWERTY
Carriage Return	Electric
Manufacturer	IBM
Printing Technology	Typeball (golf ball)
Power Source	AC Power
Power Supply	120V AC