IBM Selectric Reference Manual

9.
1.
Trigger Lever Upstop (long carriage machines) - With
the machine at rest and a clearance of .007" to .010"
exi-sting between the trigger and the lug on the torque
bar I adjust the trigger lever upstop so that it has a
clearance of .001" to .005" with the trigger lever
(Fig. 1
FI GURE 153 • Trigger Lever Upstop
(Long Carriage Only)
The trigger upstop prevents the trigger lever from boun-
ci ng as it retu rns to its rest posi ti on •
MAINSPRING AND CORDS
Gear Mesh - The proper gear mesh between the escape-
ment cord drum and the carrier return pinion involves
two adj ustments. Both must be consi dered together.
a.
Adjust the operational shaft laterally so that the
crown surfaces of the escapement cord drum gear
and the carrier return pinion are even (Fig. 154).
On the 11 inch machines, the position of the
operational shaft is controlled by the operational
cam ratchet and the shift clutch arbor. On long
carriage machines the position is controlled by a
These Two
Escapement Gear Shou Id
Be Positioned For .002"
To .004" Backlash At
Tightest Point
Surfaces Even
•
Bearing
Carri er Return
Pinion
Adjust Operational Shift End Play By Shift
Arbor And Operati ona I Clutch Ratchet
FIGURE 154. Gear Mesh And Operational Shaft Adjustment
2-54
collar set screwed to the shaft and the shift clutch
arbor. Be sure to maintain .002" to .004" end
play in the operational shaft.
b. The escapement cord drum gear should be adjusted
forward or back to obtain .002" to .004" backlash
at the point of tightest mesh with the carrier return
pinion. Be sure that no binds exist throughout the
travel of the carrier (Fig. 154).
CAUTION: The mainspring tension should be RE-
LAXED
before the escapement cord drum gear is
loosened. The cord tensi on shou Id a Iso be re laxed
by removing the cord from the pulley on the cord
tension arm. Be sure that no end play exists in the
escapement shaft before attempting the gear mesh
adjustment.
NOTE: No attempt should be made to adjust the
cord tensi on wi th the escapement cord drum because
the drum is set-screwed to a flat spot on the escape-
ment shaft.
2. Tab Governor Pinion - Adjust the tab governor pinion to
have .002" to .004" backlash at the point of closest
mesh with the escapement cord drum gear. Adjust the
pinion by moving both the tab governor hub and collar
located on each side of the pinion. The pinion should
have a minimum of end play yet sti II rotate freely (Fig.
155) •
3.
Escapement Drum Gear
Position Tab Governor
Pinion For .002" to
.004" Backlash
Operationa I Shaft
Tab Pinion Gear Collar
Tab Governor Spring
Tab
Governor Arbor
FIGURE 155. Tab Governor Pinion
Cord Tension -
With the cords properly threaded (Fig.
156A & B) adjust carrier return drum until the flange of
the right hand transport pulley is clearing side frame by
1/8 to 1/4" (Fig. 156C).
I I
I I
, I
I r; - -.-
r
J~ ---
r..l
II
I
FIGURE 156A. Carrier Return Cord Threading

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