IBM Selectric Manual

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Intermediate
Lever
~~:-~
":,, f\1'\1'\f\f\f\ " f\ _
~---t--
.005" T:.~l:~~
FIGURE 129. Intermediate Lever (Early Level)
CARRIER RETURN MECHANISM (OLD STYLE)
Be sure that the print escapement and operational control ad-
justments are correct before attempting the carrier return ad-
justments.
1.
Carrier Return Latch Height (721 only) - With the carrier
return/index cam at rest, adjust the carrier return latch
height by the adjusting screw on the backplate (Fig. 130)
so that the latch wi II pass under the cam follower by
.00111 to .010
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when it is released to the rear.
Adjusting Screw
FIGURE 130. Carrier Return Latch Height
Adjustment (721)
The latch height ad justment insures maximum throw for
the latch and that it wi \I move under the cam follower
freely.
CAUTION: Any change in the carrier return latch
height directly affects the front to rear position of the
latch (with respect to the cam follower) when the ma-
chine is at rest. See adjustment #4 in the Operational
Control section.
NOTE: Onearly level long carriage machines the car-
rier - return latch height cannot be obtained until after
the correct pawl clearance and cl utch latch overthrow
adjustment is obtained.
46
2.
3.
Pawl Clearance (721, 723 and 725) - Adjust the clutch
latch eccentri c so that the escapement pawl wi \I clear
the rack teeth by .005" to .015" when the latch is be-
ing held down by the keeper (Fig. 131).
The ad justment insures that the escapement pawl wi II not
drag along the rack during a carrier return operation and
that the pawl will beallowed to re-enter the rack quickly
~~ ~he ':0ITlr'€'tinn nf thE> rE>turn operation.
.005
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To .015
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Clutch Latch
Eccentric
Latch Held Down
By Keeper
FIGURE 13l. Pawl Clearance Adjustment
Clutch Latch Overthrow (721 only) - With the platen
and feed rolls installed and the index selector lever set
inthe double index position, manually operate the car-
rier return cam to the hi gh point whi Ie observing the mo-
tion of the clutch latch. It should overthrow the latching
surface ofthe keeper by .030" to .040
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(F i g. 132). Ad-
just the carrier return latch arm ad justing screw to obtain
this condition.
NOTE: Installing the platen and feed rolls, plus setting
the index selector lever in the double index position,
permits the overthrow adjustment to be measured while
the system operates under a load.
Adjusting Screw
FIGURE 132. Clutch Latch Overthrow
Adjus tment(721)
Clearance

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