Ref
Function
Name of part and description
and 118).
symbol
Ref
Rotates and feeds
Function
LEAD SCREW ASSEM-
A
Name of part and description
symbol
drum assembly.
BLY: lead screw.
End thrust bearing.
LEAD-SCREW PRES-
B
DRUM, facsimile trans- Holds, rotates, and
SURE PLATE.
spirals copy.
ceiver.
coupled lead screw to
DRIVE DOG ASSEM-
C
DRUM SLEEVE.. . . . . . Outside of drum.
A
motor clutch.
BLY.
K E Y - - - - - - - - - - - - - - - - - - Drives drum through
B
Causes dog latch to
D
CAM, dog latoh ---------
contact with key-
to disengage from
way in lead screw.
clutch.
CLAMP, paper and film- Secures copy to drum.
C
Supports right-hand
E
BLOCK, bearing: rh----
CONTROL LEVEL, Opens and closes
D
end of lead screw.
paper and film
paper and film clamp.
Supports left-hand
BLOCK, bearing: 1h. ----
F
clamp.
end of lead screw.
LEVER, cam plate ----- Operates cam con-
E
Preloads thrust bear-
SPRING ---------------
G
trolling half nuts.
ing.
Reflects light during
F
RING, phasing ----------
Drives lead screw
ARM, dog trip -----------
H
primary
from
HALF NUTS ----------- Feed drum along lead
G
clutch.
screw.
Drives lead screw
LATCH, dog ------------
I
RETAINER, half nut--- Mounting for half
H
from secondary
nuts and left-hand
clutch.
end drum support.
Dust shield for bear-
PLATE, drum stop ----B-
J
STOP, drum ------------ Bumper between
J
ing and drum stop.
drum and bearing
Lead-screw bearings.
EARING, ball -------
K
block.
a. General. Dirt on the lenses or poor adjust-
ment of the optical system will cause insufficient
light on the photocell.. Before tracing trouble,
a. Cleaning. Clean the lead screw thoroughly
clean and adjust the system in accordance with e
with solvent (SD). Be careful not to scratch
the threaded portion. After cleaning, inspect for
100 transmissions, Refer to figure 120 for trans-
scratches and nicks, using a magnifying glass.
mitter optical system used in Facsimile Trans-
If nicks appear in the threaded portion, the threads
ceiver TT-1/TXC-1 through TT-1C/TXC-1.
sometimes may be chased by a skilled machinist
Refer to figure 121 for transmitter optical system
working with a hand tool. Any nicks or dents
used in Facsimile Transceiver TT-1D/TXC-1,
in the other portion of the lead screw should be
TT-1E/TXG-1, and TT-1F/TXC-1.
emoothed out with a fine oil stone. Examination
b. Inspection. The following points in the
of the lead screw should include an inspection
transmitter optical system muet be examined for
of the bearing (K, fig. 119). Replace the bearings
defects before starting any repair work:
that cause the lead screw to bind.
(1) Exciter lamp. The exciter lamp may have
b. Keyway. Nicks in the keyway will cause
a poor internal contact which causes it to
jitters in the recorded copy. A nick sometimes
flicker. Try a second lamp known to be
can be smoothed out with a very fine three-cornered
good to determine whether the first lamp
file; the file mark may be smoothed out with a
is at fault. Be sure the lamp is in ita
fine stone.
right position and not rotated 180 in the
c. Lubrication. After a lead screw has been
socket. Check the position each time
cleaned, inspected, and repaired, lubricate it as
the lamp is removed.
directed in paragraph 46.
(2) Socket. Examine the socket for good con-
d. Lead Screw, Dog, and Bearing Parts Descrip-
tact. Be sure there is no corrosion.
