IBM Selectric Reference Manual

SHIFT MAGNET ASSEMBLY
NOTE: Shift mechanism adjustments must be correct before
the following adjustments are attempted.
1. Hinge Plates (Fig. 74) - Position the hinge plates with
the armatures manual I y at.tracted to obtai n .001
11
to .003
11
clearance between the armatures and hinge plates.
This clearance insures free operation of the armature.
With no clearance and oil on the two surfaces the arm-
ature would have a sluggish operation. Excessive clear-
ance may cause slow operation due to the relationship
between the magnetic field and armature.
Hinge Plate
(Top View)
Armature Energized
2.
U.C.
I
I
I
I
I
_~ .... __ .00111 to .003" Clearance
Yoke ;
Adjusti~g Screw
..... ,,.iiiIIiiI ....... ~
Hinge Plate
L.C. Magnet
Adjusting Screw
FIGURE 74. Hinge Plate5
Armature Stops (Fig. 75) - Position (magnets energized)
so that the armatures clear their yokes by .003" to
.007".
Adjusting Screws
L.C. Magnet
.003
11
to .007
11
Yoke
FIGURE 75. Armature Stops
.003" to
.007"
3.
The ad justment insures that the armature wi II not touch
magnet core. I f an armature does touch a core it may
be held by residual magnetism.
Armature Backstop, 11 Inch Machine (Early) (Fig. 76) -
Adjust the armature backstop (UC magnet - armature at
rest) so that the armature clears the core by .028
11
•
Insufficient clearance may reduce the armature motion
enough to cause shift failure. Excessive clearance may
cause shift failure since the magnetic field may not be
able to pull in the armature.
Armature At Rest
.028
11
Air Gap
U.C. Magnet
4.
5.
Core
FIGURE 76. Armature Backstop, 11 Inch Machine
U~ Magnet Assembly - Position so that its mounting
screws are centered in the elongated holes with the
hinge plates (Fig. 74) parallel with the assembly mount-
ing plate.
LC Magnet Assembly - Position as follows:
a. Front to Rear - LC armature (energized) clears the
UC armature (at rest) by .010" (Fig. 77).
Magnet
Armature Energized
L.C. Magnet
FIGURE 77. LC Magnet Assembly (Front to Rear)
2-20

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