Teletype 28 Manual page 11

ISS 8, SECTION 573·115-700TC
2. 04 Selector Mechanism (continued)
S~LECTOR
ARMATURE SPRING (For Units With Two Anti-Freeze Buttons on Selector Armature)
(1) Requirement (Preliminary)
With start lever, marking and spacing lock levers on high part of their cams, hook
scale under end of armature extension (hold as nearly vertical as possible). It should
require
0. 020 amperes
14 grams
0. 060 amperes
21 grams
to pull rear button against its pole piece.
To Adjust
Position adjusting nut.
Note_!: This spring tension can be adjusted for maximum selector performance only when the
printer is connected to the specific circuit over which it is to operate under service conditions.
Since there are several operating speeds and since circuits vary widely, it is impossible to
adjust the spring for maximum performance at the factory. The foregoing spring tension
requirement is given to permit operation prior to measurement of receiving margins.
Readjustment made to obtain satisfactory receiving margin should not be disturbed in order
to meet the requirements of this adjustment. The final spring tension should be held as
close as possible to the values given above - consistent with good receiving margins.
POLE PIECE
/J.___
ARMATURE SPRING
I
-
/
ARMATURE
EXTENSION
FRONT
1
BUTTON\ REAR BUTTON
ARMATURE
(Right Side View)
(2) Requirement (Final)
When a Qistorti.:>n test set is available, refine selector armature spring adjustment to
meet selector receiving margin (2. 11).
Note 2: With selector magnets energized, front anti-freeze button must be in contact
with its magnet core.
Page 11