IBM Selectric Reference Manual

NOTE: The following adjustments, thru and including
number 11, apply only to printers with dual velocity key-
board.
a. With the machine resting on its back, slowly hand
cycle a high velocity character unti I the leading
edge of the print shaft keyway lines up with the
center of the roller pin on the cam follower (Fig.
142.3).
I~,- _, - ___ - __ q
I ------ I
1-
~ 'I~
r I I~
.... ~~I ~p~~~
--~!I I~I ~
11
:D"
I
I I
l_~~1
Pin
I I
I I
L ____ -.= = =
I)
I~
.... -j
I I
I I
1--'-
I (-- Keyway
I I
I
=~ J
FIGURE 142.3 Keyway In Line With Roller
b. Loosen the stop screw locking nut and back out the
stop screw approximately two turns. (The roller
should be resting against the cam at this point.)
c. With the machine resting on its back, place a .001"
or .002" feeler gauge between the print cam and
the follower roller (Fig. 142.4). This can be ac-
complished by manually holding the rocker toward
the platen while inserting the feeler .gauge from the
front of the carrie'r (to the right of the carrier point-
, er) just above the line lock bracket. With the
gauge in position, allow the rocker to come back
to rest. The feeler gauge should become trapped
between the roller and the cam. Then, slowl y turn
the stop screw in until a minimum drag is felt on
the feeler gauge as it is withdrawn.
FIGURE 142.4 Feeler Guage Trapped
2-47
8.
d. Tighten the locking nut without moving the screw.
NOTE: This adjustment may be checked by apply-
ing a light"film of #17 grease on the print cam (in
the area indicated in Fi-9. 142.5) and then observ-
ing the track that the roller. makes in the grease
when the machine is hand-cycled. If the stopscrew
has been adjusted properly, the roller track in the
grease should begin at point "A II (Fig. 142.5) which
is the beginning of the second low dwell on the
print cam.
FIGURE 142.5 Roller Track In Grease
If the roller track begins before point "A ", the
roller is adjusted too close to the print cam when
the machine is at rest. Improper roller to cam
clearance may cause the roller to drag on the print
cam as it shifts during a low velocity selection.
Thus, the roller may fai I to shift, or shift improper-
Iy. If the roller is adjusted too close to the com ot
rest, it may receive a ski-jump effect from the print
cam as it attempts to follow the print cam from the
first low dwell to the second low dwell. This will
create excessive noise and wear along with an ad-
verse effect on the type head impact velocity.
If the roller track begins after point "A ", the roller
rests too far away from the fi rst low dwe II of the
print cam and a loss in typehead velocity may re"
suit.
Velocity Control Cable Adjustments - The velocity con-
trol cable is adjusted to satisfy the following conditions:
a. Carrier Cable Clamp - Loosen the clamp screw and
slide the cable sheath left or right under the clamp
until the end of the sheath is fl ush to .010" recess-
ed with the right hand edge of the clamp (Fig.
142.6). This adjustment prevents the yoke actuat-
ing lever from choking off against the cable sheath.
b. Carrier Cable Guide - Position the cable guide
horizontal and as high as possible without binding
the cabl e agai nst the carri er (Fi g. ] 42 .7). This
adjustment holds the cable up as high as possibl.
yet allows it to sl ide freely front and rear as the
carrier moves along the writing line.

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