IBM Selectric Reference Manual

d. Head play - it should be .045" measured
at the typehead skirt. If excessive head play is
suspected the ball joint should he replaced and the
typehead homing adjustment refined.
CAUTION: Excessively advanced or retarded tim-
i ng can cause parts damage as we II as poor hori-
zonta alignment or improper selection. This could
happen if the detent entered the wrong notch or re-
mained in the notch too long.
NOTE: Be sure to maintain .002" to .004" end
play in the print shaft.
14. Shift Motion - The shift arm adjusting screw (Fig. 132)
should be adjusted in or out to obtain 180
0
rotation of
the typeh'3ad during a shift operation.
Lock Nut
LA TE STYLE
FIGURE 132. Shift Motion Adjustment
The
adjustment can be checked by observing the detent-
ing in the lower case compared to the upper case using
a
-5 character. The detent MUST enter the lower case
notch EXACTLY the same as it does the upper case notch.
Check by half-cycling the machine cmd manually with-
drawing the detent. Remove the head play clockwise
and allow the detent to re-enter slowly. A final check
can be made by comparing the detent withdrawal timing
ofthe upper and lower case. They must be exactly al ike.
Maladjustment can cause misal ignment in the lower case
while the upper case remains good.
CAUTION: Be sure that the shift cam is detented at
each position during the check and that the cycle shaft
is
properly latched at the half-cycle position.
15. Final Check - After completing the foregoing adjust-
ments, a final check should be made to see if any re-
finements are necessary. Compare the coarse al ignment
of 0 rotate compared to +5, -1, -3, -4, -5. The band
wi dth of th i s group shou I d not exceed .030" and none of
the group should detent closer than .010" to the center
of the notch when the head play is removed in the nega-
tive dl, .:-dion.
The following table can be used to diagnose the cause of
excessive band width between a 0 rotate and +5, -1, -3,
2-41
-4, -5. If an excessive band width exists, it will be
greatest among these characters. In making the diagnosis
follow the sequence as listed.
Excessive Band
Width Between
o (zero) and -1
-3 and +5
-3, +5 and 0 (zero)
-5 and -3
Cause
Incorrect balance
Incorrect rotate arm motion
Incorrect latch clearances
Incorrect paddle adjustmenl
Unwanted compensator roller droppage may result from
one or more of the following.
a. Improper detent timing
b. Malselection (popping latches)
c. Incorrect rotate spring tension or damper spring ten-
sion.
d. Binds in the typehead, upper bal I socket, rotate
shaft, rotate pulley, or rotate spring.
e. Binds in the compensator or lever system.
f. Loose differential mounting bracket.
g. Excessive band width or head play.
If the band width appears to be all right but the align-
ment is not satisfactory, check the following items:
a. Detent timing
b. Playorbindsinthe tilt or rotate detents. Side play
in the rotate detent can be checked by holding down
the interposer for the letter "N" so that it repeats
for a full line. Move the carrier back manually
and repeat the operation without indexing. The
second I ine should cover the first I ine exactly. If
any of the characters are shadowed, side play in
the rotate detent cou I d be the cause.
c. Loose fitting upper ball socket.
d. Excessive play in the carrier or rocker.
e. Binds in the rocker parts.
f. If the -5 characters vary horizontally, improper
damper spring tension could be the cause.
g. Improper tilt adjustments can cause poor horizontal
al ignment by delaying the detent seating.
NOTE: After the machine has been in use for some
time, wear in the tape system will allow the typehead
to drift in the negative direction. It is not necessary to
slip the rotate shaft within the rotate pulley to REFINE
the typehead position. The proper position may be gain-
edbyrefining the eccentric stud adjustment. Be sure to
RESEATthe compensator roller after changing the eccen-
tric stud adjustment. (Maintain the roller position 1/16"
from the topofthe slot by adjustment of the rotate link.)

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