IBM Selectric I/O Manual Of Instruction page 40

Engineer. The more accurate the adjustments, the less var-
iation there will be in the ti It ring position for the different
characters and the more narrow the band width will be. It is
not necessary to achieve a band width any smaller than the
given set up tolerance.
Coarse a I ignment for each tilt positi on can be observed in
the following manner:
a. Half-cyc Ie the machine under power by
placing the Hooverometer handle in position
to block the cycle clutch sleeve before
striking a keylever (Fig.
83).
Hooverometer Handle
Vertical And Against
---,--+ ....
LCltch Pivot Pin
When Hal'f Cycling Machine
Make Certain Cam Shaft
Is Detented
FIGURE
83.
Half Cycling Operation
After half-cycling, turn the machine off and
make certain that the cycle shaft is resting in
a half cycled position by observing the posi-
ti on of the check pawl in the cycle shaft check
ratchet. The check pawl should be detented
b.
c.
in the half cycle notch on the check ratchet
(Fig. 84).
FIGURE 84. Half Cycle Operation
Half-cycling is done under power so as to in-
c I ude a II the stresses on the system.
Manua Ily withdraw the detent and remove the
ti It ring play by pressing Hght Iy to the rear on
the upper ba II socket.
Allow the detent to re-enter the ti It ring notch
whi Ie observing the point where the detent
first contacts the side of the V-shaped notch.
31
Performing this check for each ti It position provides a method
of visually measuring how much coarse alignment variation
there is in the system, and also which adjustment (or adjust-
ments) is causing the variation. Each adjustment in the sys-
tem affects coarse alignment in a different manner and shows
up in a definite pattern. By observing the pattern, a mal-
adjustment in system can easi Iy be diagnosed.
Example: Figure 85 illustrates a coarse alignment check of
the four tilt positions.
O-Tilt
1-
Ti It
2-
Tilt
3-
Tilt
FIGURE 85. Course AI ignment Check
Note that there is a progressive loss of motion to the ti It ring
from a tilt zero to a ti It three. This indi cates that the ti It
arm (Fig. 86) is receiving equal increments of motion from
the ti It differentia I system, but is not mu Itiplying the motion
enough to satisfy the ti It ring.
FIGURE 86. Tilt Differential
By moving the tilt link down in the elongated slot on the tilt
arm, more motion wi II be produced to the ti It ring for the
same increments of motion produced by the tilt differential
system.
Alignment can be separated into two stages: IIcoarse align-
ment
ll
and IIfine alignment ll
•
Coarse alignment is the intro-
duction of the detent into the wide portion of the detent
notch. Fine a lignment occurs after the detent moves up into
and seats in the notch. Once the ti It detent has fu lIy seated
in the ti It ring notch, any vertical misalignment problems
cannot be attributed to coarse alignment adjustments. The
problem lies in the carrier and rocker area and usually is
caused by one of the following: too much upper ball socket