IBM Selectric Maintenance Manual page 112

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
whee I. The improved bite wi II 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
D esc ri pti on
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-
qui re that these paw Is be replaced more frequently.
S.H. OPERATIONAL INTERPOSER RESTORE BAIL
ADJUSTMENT
When the operati ona I interposer restore bai I requi res
readjustment to insure positive overthrow of the in-
terposers on thei r latchi ng 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" more in-
terposer restoring motion. The clip is PN 1110093
and is described as a feed roll retainer clip 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 fail-
ures in the operational area are encountered and it
is suspected that these springs are fai ling to properly
trip the operational cams, all the interposer springs
should be replaced with the following new part
numbe~.
.
4-4
Part No.
150047
1134948
Desc ri pt i on
Spri ng, spacebar interposer
Spri ng, operati ona I 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 tripped off,
travels to the rear, but does not trip the space cam.
If the next pulse to the printer is to the print mag-
nets, this pulse will start to activate the 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 durati on of
pulse on the print magnets that a malselection wi
n
resu It due to improperly selected latches.
2.18 S.
H.
100" MAIN SPRING
Effective with I/O printer SIN 4607171, all Se-
lectric I/O
printe~
wi II incorporate a 100" main-
spring.
The old 75" mainspring, PN 1124519, will no longer
be used. The new 100" mainspring, PN 1164342, will
be avai lab Ie for field replacement and is directly in-
terchangeable with the old 75" mainspring.
The new 100" mai nspri ng may easi Iy be i denti fi ed by
the "100" stamped on the rear of the mai nspri ng cage.
This new spring will 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.