IBM Selectric Manual

b. New Style Paper Feed Mechanism - With the feed
roll tension spri ngs disconnected, the center support
bracket (Fig. 180) should be positioned so that the
forward lug just touches the underside of the feed
roll shaft whi Ie the rear lug just touches the top of
the carriage tie rod. The center support bracket
should not bow the copy control shaft.
Carriage Tie Rod
Feed Roll Shaft
Arm Assembly
Center Support Bracket
FIGURE 180. Center Support Bracket
4. Feed Roll Tension - P lace the feed roll tension spri ngs
in
the hole of the front feed roll arms that will provide
the following tension measured at the front feed roll
pivot points.
721 - 2-3/4 to 3-1/4 pounds
723 and 725 - 2 to 2-1/2 pounds
5. Feed Roll S ide Play
a. Old Style - The ri ght hand paper feed mounti ng arm
on
the 721 and the left and right hand paper feed
mountingarmson the 723and 725 should be adjusted
to provide the rear feed roll shafts with an end play
of .015" to .030" when the feed rolls are against
the platen (Fig. 179).
b. New Style - The right hand front feed roll arm
assembly on the 721 and the left and right hand
front feed
roll arm assembl ies on the 723 and 725
should be adjusted to give end play to the feed roll
shaftsthat will not permit them to contact the sides
ofthe openings in the deflector but wi II permit them
to roll freely (Fig. 180).
6. Feed Ro II Ad j ustment
a. Old Style-Adjusttheeccentricswiththehighpoints
to the rear so that three tab cards inserted between
the platen and the rearfeed rolls will cause a clear-
ance of .008" to .012" between the front feed rolls
andtheplaten(Fig. 181). The clearance should be
equal on both ends of the feed roll.
61
Make Adiustment Here
Front Feed
Roll Arm
FIGURE 181. Feed Roll Adjusting Eccentrics
(Old Style)
b. New Style - The front feed roll ad justing arms should
be adjusted as follows: When two tab cards are
placed between the front feed rolls and the platen,
the rearfeed rolls should clearthe platen (Fig. 182).
When one tab card is placed between the front feed
rolls and the platen, the rear feed rolls should touch
the platen.
Check CI earance Here
Loosen Here
FIGURE 182. Feed Roll Adjusting Arm (New Style)
7. Paper Re lease - Ad just the feed roll re lease arm (Fi g. 183)
toobtain a release clearance of .055" to .065" between
the rear feed roll and the platen.
Excessive clearance can cause interference between the
front feed roll and the carrier; whereas insufficient
clearance will not permit straightening of thick paper
packs.
NOTE: The clearance should be the same at each end
of the feed roll. The clearance can be equal ized by
adjusting either the left or right feed roll release lever
(Fig. 183).

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