IBM Selectric Reference Manual

2.15
2.16
2.17
S. H. OPERATIONAL CAMS (EXTRA CYCLES)
The cam wheel mounting stud has been extended so
as
to provide greater release lever bite on the cam
wheel. The improved bite will eliminate extra cy-
cles of the Operational cams caused by the release
lever slipping off the side of the clutch wheel.
Part No.
1159886
1159267
1159269
Description
CR cam
SB cam
Ratchet
NOTE: The operational cam pawls should be
checked frequent Iy for wear. They shou Id be re-
placed approximately every 15 months in machines
experiencing normal usage. Machines experiencing
heavy usage such as 24 hour/day operation wi II re-
quire that these pawls be replaced more frequently.
S. H. OPERATIONAL INTERPOSER RESTORE BAI L
ADJUSTMENT
When
the operational interposer restore bai I requires
readjustment
to insure positive overthrow of the in-
terposers on their latching surface, it is no longer
necessary
to form the lugs on the operational inter-
poser restoring bai I in the area where each interpos-
er contacts the restore bai I when being replaced.
This clip will provide approximately .015
11
more in-
terposer restori ng moti on. The c lip is PN 1110093
and is described as a feed roll retainer c lip used on
standard
typebar machines. This clip may be ob-
tained through any local branch office stockroom.
S. H. OPERATIONAL INTERPOSER SPRINGS
The operational interposer springs have been rede-
signed to provide greater spring tension and more re-
liable tripping of the operational cams. When fai l-
ures in the operational area are encountered and it
is suspected that these springs are failing to properly
trip the operational cams, all the interposer springs
should
be replaced with the following new part
numbers.
5-4
Part No.
150047
1134948
Description
Spri
ng, spacebar interposer
Spri ng, operati ona I interposer
(a II except space)
Note: Occasional malselections may also be caused
due to failure of the interposer to trip the space cam.
This can happen if the space interposer is tripped off,
trave Is to the rear, but does not tri p the space cam.
If the next pulse to the printer is to the print mag-
nets, this pulse wi II start to activate t,he print mag-
nets and then the interposer wi II tri p the space cam
opening
C-5 and therefore cut the pulse to the print
magnets. This wi II cause such a short duration of
pulse on
the print magnets that a malselection wi n
result due to improperly selected latches.
2.18 S. H. 100" MAIN SPRING
Effective with I/O printer SIN 4607171, all Se-
lectric I/O printers wi II incorporate a 100
11
main-
spring.
The old 75" mainspring, PN 1124519, wi II no longer
be used. The new 100 II mai nspri ng, PN 1164342, wi II
be avai lable for field replacement and is directly in-
terchangeable with the old 75" mainspring.
The new
100" mainspring may easily be identified by
the 11100 II stamped on the rear of the mai nspri ng cage.
This new spring wi II add greater torque to the carrier
escapement and tab operati ons .
2.19 S.H. ESCAPEMENT SHAFT BEARINGS DRY (USE
#10)
Tap shaft
lightly to re-align.

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