TM 55-4920-244-14
e. Insert replacement lamp in lamphold-
(4) Secure deck assembly (4) to box
er, press in, and rotate 90 degrees clockwise.
assembly (18) with screws (5).
(5) Turn shaft of voltage regulator
f. Reinstall dust cover on bottom of gal-
(7) to its extreme counterclockwise travel.
vanometer.
(6) Carefully position knob (3) on
g. Carefully lower deck assembly (4, fig.
shaft of voltage regulator with pointer aligned
4-6) on
flange of
box assembly (18).
on zero and tighten setscrews.
NOTE
NOTE
The deck gasket should
Insure that shaft of volt-
be replaced at each re-
age regulator remains at
moval; however, if a new
its extreme counterclock-
deck gasket is not avail-
wise travel with pointer
able, exercise care to pre-
of knob (3) aligned on
serve the original deck
zero while tightening set-
gasket.
screws.
h. Perform steps (4) through (7) of
(7) Install probe storage compart-
ment.
4-33. Replacement of
Galvanometer
4-34. Replacement of
POWER ON
Lamp
(GALVO-1 and GALVO-2) Lamps.
a. Perform steps (1) through (3) of
a. Unscrew and remove cover from
CAUTION
b. Press in on lamp, rotate 90 degrees
counterclockwise, and lift from lampholder (76).
removed before attempt-
ing to raise deck assembly.
c. Insert replacement lamp (77) in lamp-
holder (76), press in, and rotate 90 degrees
clockwise.
its edge and properly support.
c. Remove dust cover from bottom of
d. Reinstall cover on POWER ON light
galvanometers (29, fig. 4-8) and/or galvanome-
ters (69).
d. Press in on lamp, rotate 90 degrees
counterclockwise, and lift from lampholder.
NOTE
NOTE
A blown fuse is indicated
galvanometer
by a light fixture incorpo-
Replace
rated in the fuseholder
lamps with Tungsol TS-
cap.
55 lamps, or equivalent.
If light beam pointer is
a. Rotate fuseholder cap counterclockwise
n o t bright enough or
until it springs up slightly from fuseholder
there is a double image,
(73).
use another lamp to ob-
b. Lift fuseholder cap from fuseholder.
proper
filament
tain
focus, or loosen the set-
c. Remove fuse (74 and 75) from fuse-
screw that holds the
holder cap.
lampholder in place with
d. Insert replacement fuse firmly in fuse-
a 0.050" hex key. Rotate
holder cap.
and move the lampholder
until a sharp even pointer
is obtained. Tighten set-
screw and recheck pointer
image.
rotate clockwise to tighten.