IBM Selectric Maintenance Manual page 116

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 rei nsta II the clutch ratchet, usi ng 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 shift ratchet retainer, 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 operation'al 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 reassemble 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 experi enced, check
the surface of the shift cam for a rough finish and re-
p lace 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 maladjusted shift backup roller
ion of either shift cycle, allow the detent roller 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 premature 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
shift arm does not lean front or rear, allowing the
rotate tape to ride the pu lIey flange. Insure that
shift arm pu lIey maintains at least 1/16" clearance
to the ti It pu Iley bracket.
S . H. S HI FT STOP SCREW SPACER
A spacer, PN 1090050, is now being installed under
the shift stop screw to position the head of the screw
farther from the side frame. It wi II allow more thread
engagement of the shift arm screw in the shift arm.
4.17 S.H. SHIFT INTERLOCK ARM ASSEMBLY
Shi ft interlock arm assembly "fai lure to re lease" 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-
ing hardware.
This re-design eliminates the breakage problem en-
countered with the early level 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
shifting 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-
4-8
If the Shift Release Link is adjusted too long it wi II
restrict the Shift Release Arm motion. This results
in shift failures 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 oi I or residual magnetism. This wi II
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 close to the high limit.