IBM Selectric Reference Manual

1.5
1.6
1.7
1.8
Adj ust the i ntermedi ate lever, front to rear, so that
the escapement pawl does not fall into the next rack
tooth when hand cyc Ii ng. The escapement paw I
should ride to a point just before it drops into the rack
tooth.
Binds - Check the following:
a. Feed roll mounting arm hits the tab overthrow
stop.
b. Dust covers and card holders.
c. Anvi I and front carrier shoes.
d. Rear carri er shoe.
e. Escapement cord is off its pu Iley.
f. Pinion Gear.
Adjust Tab Lever stop on the escapement pawl mount-
ing bracket so that both pawls bottom fully in the
rack and the extensi on lug on the tab lever clears the
pawls by .00111 - .003
11
.
Backspace may go a fu II space but a worn escapement
pawl wi II cause the carrier to skip ahead '1/2 space.
See Fi g. 3. 1. Look for thi s condi ti on under powered
operati on. To prevent a reoccurrence,· rep lace the
escapement pawl AND rack.
1.9 S.H. OPERATIONAL CAMS
Effective with SELECTRIC I/O Printer SIN 4609595,
. a new operati ona I cam and ratchet wi· I I be in pro-
ducti on. The cam ratchet has been extended and the
bearing surface within the cam has been elongated to
provide longer bearing life. The cam wheel mounting
stud has a Iso been extended so as to provi de greater
release lever bite on the cam wheel. The improved
bite wi II eliminate extra cycles 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
1 .10 S. H. OPERATIONAL INTERPOSER RESTORE BAI L
When the operati ona I interposer restore bai I requi res
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 restori ng bai I. A sma II retai ni ng c Ii p may be
placed on the operational interposer restoring bai I
in the area where each interposer contacts the re-
1.11
1.12
5-2
store bai I when being restored. This clip wi II pro-
vi de approxi mate Iy .015
11
more interposer restori ng
motion. The c lip is PN '1110093 and is described
as a feed roll retainer clip used on standard typebar
machines. This clip may be obtained 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 operati onal cams. When fai l-
ures in the operational area are encountered and it
is suspected that these springs are fai ling to properly
trip the operationa I cams, a II the interposer springs
should be replaced with the following new part
numbers.
NOTE: The operational cam pawls should be
checked frequently for wear. They should 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 frequent Iy.
Part No.
150047
1134948
Descri pti on
Spring, spacebar interposer
Spring, operational interposer
(a II except space)
Note: Occasional malselections may also be
caused due to fai lure of the interposer to trip the
space cam. This can happen if the space interposer
is tri pped off, trave Is to the rear, but does not tri p
the space cam. I f the next pu Ise to the pri nter is to
the pri nt magnets, thi s pu Ise wi II start to acti vate
the pri nt magnets and then the interposer wi II tri p
the space cam openi ng C-5 and therefore cut the
pulse to the print magnets. This wi II cause such a
short durati on of pu Ise on the pri nt magnets that a
ma
Ise lectj on wi II resu It due to improperly se lected
latches.
S. H. BACKSPACE CAM PAWL WEAR
Backspace cam pawls may be checked for weat dur-
ing inspection or on service calls by using this
method:
Hold
the carrier and repeatedly operate the back-
space. Worn pawls wi II slip on the cam and ratchet
and can be heard immediately.

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