IBM Selectric - Page 56

c. Half-cycle an upper case -5 character and adiust
the eccentric stud (Fig. 125) in against the ma-
chine sideframe until the -5 character detents
.010" to .020" in the negative direction from the
center of the detent notch when the head play is
lightly removed in the negative direction (Fig.
126). Make sure that the damper spring is fully
collapsed against the machine sideframe.
Eccentric Stud
(Make Adjustment Here)
FIGURE 125. Eccentric Stud
r .010" To .020"
I~
Notch In Type Head
Adjustment Made Detent
With Eccentric Stud
FIGURE
126. Eccentric Stud
After the eccentric stud has been properly adjusted
the compensator roller must be reseated by raising
it to the top of the V-shaped slot and striking a
series of -5 characters. The compensator roller
2-38
should seat 1/16" down from the top of the slot.
If it drops too little or too much the rotate link
should be adjusted and the roller reseated unti I
the 1/16" is obtained. Having the roller seat 1/16"
from the top of the slot sets up a vertical condition
between the compensating arm and the rotate arm
so
that the leverage within the arm assembly will
be the same for both positive and negative move-
ments of the arm.
In some cases it may be found that after the eccentric
stud is adjusted the roller wil I not drop but remain
trapped at the top of the V -shaped slot. If th i s oc-
curs, lengthen the rotate I ink and -then recheck the
eccentri c stud ad justment.
NOTE: The eccentric stud should always be kept
in the lower hal f of its orbit so that it wi! I tend to
turn in the tightening direction as it operates against
the sideframe. Also, if the correct detenting of the
-5 character cannot be easi Iy obtained with the ec-
centric stud adjustment the preliminary homing ad-
justment (Adj. #8) must be read justed.
d. Damper spring stop - with the typehead removed,
raise the stop so that when a lower case -5 character
is half-cycled the damper spring will just collapse
against the sideframe. Check by pull ing the com-
pensator arm away from the side frame with a spring
hook and then allow it to go back in slowly (Fig.
127) .
Machine Half Cycled To Negative 5 Lower Case Character
Damper Spring
FI GURE 127. Damper Spring Stop
The main purpose of the eccentric stud adjustment is to
stop the negative motion of the rotate arm as it approaches
the negative five position so that all of the pressure on
the compensator roller will be relaxed when the com-
pensating arm has reached its full negative position.
Assuming that no ratio change was felt in the system at
the time of making the eccentri c stud ad justment, stoppi ng
the rotate arm early to relax the pressure on the roller
wi II cause the negati ve motion of the rotate arm between