Teletype 28 - Page 112

SECTION 573-118-700TC
3, 32 Power Drive Backspace Mechanism (continued)
(Nonadjustable Backspace Magnet Assembly)
Note 1: For early design adjustable magnet assembly see 3. 26.
(A) ARMATURE SPRING
(Latest Design)
(B) LATCH EXTENSION SPRING
(Latest Design)
PLATE
MAGNET BRACKET
MOUNTING SCREWS
ADJUSTING
LINK ARM
SCREW
Requirement
r---- Min 1 oz---Max 2-1/4 oz
to start latch moving.
(Front View)
(C) MAGNET POSITION
(Latest Design)
Requirement
The armature extension should engage the latch by approximately its full thickness
when the magnet is de-energized.--------------------_J
To Adjust
Position the magnet assembly by means of its mounting screws. Tighten screws.
(D) FINAL MANUAL OR POWER ADJUSTMENT (Latest Design)
Note 2:
This is the final adjustment for all backspace mechanisms, manual
or power drive, regardless of the type of unit.
(1) Requirement
With tape in the unit, place the feed wheel shaft oil hole in its uppermost position;
operate the backspace mechanism once. The ratchet wheel should be backed one
space into a fully detented position.
Note 3: A fully detented position is defined as: With the detent roller in contact
with the ratchet wheel the punch unit feed pawl should engage the first tooth below
the horizontal centerline of the feed wheel ratchet with no perceptible clearance.
(2) Requirement
With the unit operating under power, perforate approximately two inches of tape with
the LETTERS code combination selected. Backspace twelve characters in succession
with the uait •ttl! Wlder power. Again perforate approximately two inches of tape
with the LB"M'ZRS code combination selected. Clipping of the code holes should be
held to a minimum and should not exceed more than 0.005 inches, as gauged by eye.
To Adjust
On manual operated backspace mechanisms refine the FEED PAWL ECCENTRIC
(Preliminary) 3. 26 adjustment. On backspace mechanisms equipped with power
drive, loosen the arm adjusting screw and position the adjusting plate. Tighten
the arm adjusting screw·----------------------------~
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