IBM Selectric Reference Manual

4.10
4.11
4.12
4.13
4.14
5. Remove the clutch ratchet and, without dis-
turbing the setting, tighten one screw in the re-
taining plate. Do not allow the cam to become
undetented.
6. Now reinstall the clutch ratchet, using the
same spring hole as was previously used, and
arrest it with the shift release arm (manually
lock down the shift keybutton).
7. Set the overthrow stop clearance (.010"-.025")
and securely lock the other retaining plate
screw.
S. H. SHIFT NOISE CAUSED BY ROUGH SHIFT
ARBOR
A rubbing noise in the shift mechanism may be
caused by a rough shift arbor rubbing on the shift
cam. The left end of the arbor may be polished in
the following manner:
Remove
the shi ft ratchet retai ner, shift ratchet
(notice which hole the spring is in), and shift spring
clutch. Loosen the set screws in the arbor and move
it to the right on the operational shaft and tighten
the set screws. Turn the machine on and polish the
end of the arbor with a stone or crocus cloth. Po-
sition the arbor for the correct .002" to .004"
clearance with the bearing and reassemb Ie the shift
mechanism.
NOTE: Be sure parts are free of emery dust before
relubricating and assembling.
S.H. SHIFT ARM ROLLER WEAR
If wear on the shift arm roller is experienced, check
the surface of the shift cam for a rough finish and re-
place if necessary. In the majority of cases reported
to date, wear of the roller has been caused by a rough
cam.
S.H. SHIFT BACKUP ROLLER
If the machine is locked up because the shift clutch
spring loop is caught between the arbor and the cam,
the backup roller adjustment should be checked. It
has been found that a malQdjusted shift backup roller
ion of either shift cycle, allow the detent rolle~ to
contact the cam. The detent roller shou Id not rotate
fhe cam in either direction more than approximately
1/32". Adjustments made to meet this requirement
wi II help ensure trouble-free operation.
4.15 S.H. SHIFT ARM BRACE ADJUSTMENT
4.16
Some pr~mature tape wear may be traced to the shift
arm not moving in a true vertical plane. Check the
adjustment of the shift arm brace to assure that the
shi ft arm does not lean front or rear, a Ilowi ng the
rotate tape t9 ride the pu Iley flange. Insure that
shift arm pulley maintains at least 1/16" clearance
to the ti It pu Iley bracket.
S. H. SHIFT STOP SCREW SPACER
A
spacer, PN 1090050, is now being i nsta lied under
the shi ft stop screw to posi ti on the head of the screw
farther from the side frame. It wi II a Ilow more thread
engagement of the shift arm screw in the shift arm.
4.17 S. H. SHIFT INTERLOCK ARM ASSEMBLY
Shift interlock arm assembly "fai lure to release" may
result from a
slight burr on the interlock spring in the
area where it contacts the ratchet. The burr may be
easi Iy removed with a fi Ie or flexstone.
4. 18 S . H. C7 CAM
The shift clutch ratchet has been redesigned to ac-
commodate a new C-7 cam for 1052 and 1053 SE-
LECTRIC I/O Printers. The new PN is 1159409. This
part will replace old PN 1128218. The shift clutch
ratchet requires the use of a new C-7 cam and mount-
i ng hardware."
This re-design eliminates the breakage problem en-
countered with the early leve I C7 cam.
Part No.
1159408
1159409
1159262
257985
1127163
Description
Cam, C-7
Ratchet
Screw, Cam Mtg.
Washer
Nut
allows the right hand operational shaft bearing to be 4.19
S.H. SHIFT TO UPPER CASE
cammed
in, thus i ncreasi ng the clearance between the
shift arbor and cam. This condition can be observed
by watching the bearing for movement to the left when
shifti ng to upper case.
S. H. SHIFT BACKUP ROLLER ECCENTRIC SHAFT
The
pusher end of the large spring hook may be used
as a
wrench to adjust the shift backup roller eccentric
shaft .
S. H. CHECK FOR SHIFT DRIVE ADJUSTMENT
The
shift spring drive and proper brake adjustment can
be checked manua lIy, holding the detent roller away
from the cam and operating the shift. After complet-
5-8
If the Shift Release Link is adjusted too long it wi II
restri ct the Shift Re lease Arm moti on. This resu Its
in shift fai lures when shifting to upper case in out-
put mode.'
4.20 S.H.
The Lower Case Armature may stay attracted to the
core due to oil or residual magnetism. This will
prevent latchi ng in upper case and therefore cause
a simultaneous shift to lower case and print opera-
tion. Clean the Armature and core. Readjust the
armature stop for .003" - .008" clearance between
the armature and core. It is desirable to maintain
the adjustment c lose to the high limit.

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