IBM Selectric - Page 45

3.
The rotate pulley is secured to the rotate shaft by a
wedging block and a set screw. The pulley set screw is
accessible from below with the carrier centered over the
cycle shaft and the shift in the upper case. After loosen-
ing the set screw the grip of the block on the shaft must
be broken by rotating the type head counterclockwise
manually while blocking rotation of the pulley. This
can be done by inserting the 3
11
screwdriver at the rear
between the notch in the pulley and the tape guide block.
Be careful not to damage the tape or pulley with the
screwdriver. DO NOT rotate the type head clockwise
against the tension of the tape in an effort to break the
pulley loose. Tape breakage or other parts damage may
result.
NOTE: The height of the lower ball socket is controlled
by a shim located between the lower ball socket and the
tilt tube or yoke. The height relative to the tilt ring
must
be controlled in order to insure proper operation
of the ball joint. If disassembly of the rocker is ever
necessary, the shim must be reinstaHed.
Ti It Ring - The upper ball socket should be centered over
the lower ball socket within .002
11
• It is adjusted by
moving
the tilt ring left or right after loosening the tilt
ring'pivot pin set screws. A~I side play of the tilt ring
should be removed by the pivot pins while still allowing
the ti It ring to pivot freely.
If the tilt ring is not properly centered, the rotate posi-
tion of the head can vary slightly as the head is tilted to
the different ti It positions. This could constitute a portion
of the band width in the rotate system.
The tilt ring is centered at the factory and every effort
should be made to maintain its centered position. If tilt
ring removal or replacement is necessary, a feeler gauge
should be inserted between the tilt ring and the yoke to
determine the clearance before the tilt ring is removed.
The ti It ring should be replaced to the same clearance.
The tilt ring can easily be removed if the machine is half
cycled to a two tilt position. On machines prior to the
gearless tilt mechanism, care should be taken to insure
that the tilt sector gears are properly meshed whenever
the ti It ring is installed. The rear tooth of the tube sector
gear should enter the second notch of' the tilt ring sector
gear (Fi g. 95).
Minimum Play In
Upper Ba II Socket
Tilt Ring Spacer
Tube Gear
Shim
Enters Second Notch Of
Tilt Ring
FI GURE 95. Upper Ball Socket Adjustment
4.
5.
2-27
CAUTION: Side play in the tilt ring can cause poor
horizontal and vertical alignment. It can also affect
impression.
Upper Ball Socket - The upper ball socket must rotate
completely free of binds with little or no up and down
play. The adjustment is made by raising or lowering the
tilt ring spacer by installing thicker or thinn'er shims at
the front and rear (Fig. 95).
In order to check the upper ball socket for binds it is
necessary to remove the ball joint so that the upper ball
socket can be rotated by hand. This can be done either
by removing the ti It ring and upper ball socket together
and checking them off the machine or by removing the
upper ball socket and replacing it without the ball joint.
I f the ti It ring is removed, its position relative to the
yoke must be checked by a thickness gauge before re-
moval.
NOTE: If the upper ball socket, tilt ring, or tilt ring
spacer are ever replaced by new parts, the shimming
adjustment must be checked.
CAUTION: Vertical play in the upper ball socket will
affect vertical alignment and impression because the
typehead wi II not maintain a definite position.
Also, care must be taken to insure that the entire rotate
system is free from binds. A bind in the upper ball socket
can result in poor horizontal alignment ifthe rotate detent
fai Is to fully seat in the detent notch before print occurs.
An excessive bind can cause unwanted roller droppage
in the wear compensator during a negative selection.
Binds in the system (carrier area) can be checked by
manually operating the shi ft arm in and out.
Tilt Detent - Adjust the guide and pivot screws so that
the tilt detent will operate freely with no side play
(Fig. 96).
Tilt Detent
Pivot Screw
FIGURE 96. Tilt Detent Adjustment