*TB SIG 312
DEPARTMENT OF THE ARMY TECHNICAL BULLETIN
PROCEDURE FOR REPLACING ELECTRON TUBES IN
ARMY SIGNAL EQUIPMENT
Headquarters, Department of the Army, Washington 25, D. C.
19 September 1962
1. Purpose. Studies of maintenance procedures
for example, may function with one tube
employed in the replacement of electron tubes have
and not with another, although both tubes
shown that more than one-third of all electron tubes
are new. If possible, retain any tube that is
have been discarded erroneously as "faulty." The
replaced until its usefulness is checked
purpose of this technical bulletin is to outline procedures
with suitable test equipment
that will help to prevent or to reduce this waste of
material by establishing a uniform guide for checking
(2) Remove the other substitute tubes one at a
and replacing all electron tubes used in Army signal
time and reinsert the original tubes in the
equipment.
sockets they occupied originally. Check the
2. Procedure.
a.
Inspect all cables and
operation of the equipment after each
original tube is reinstalled. If the equipment
connections and check the general condition of the
fails to operate when any original tube is
equipment before any electron tubes are removed.
reinserted, discard this tube and reinstall the
b. After this general inspection, localize the trouble
substitute tube. Continue to reinsert the
original tubes until they all are reinstalled or
to a particular unit or section of the equipment.
have been proved unsatisfactory. DO NOT
c. If a tube tester is available, remove each tube
LEAVE A NEW TUBE IN A SOCKET IF THE
EQUIPMENT OPERATES SATISFACTORI-
from the set and test it individually. Do not substitute
LY WITH THE ORIGINAL TUBE.
new tubes unnecessarily; replace only those tubes that
are proved to be defective (par. 3).
e. If only a limited number of spare tubes is
d. If a tube tester is not available, check the tubes
available, proceed as follows:
by substitution. Proceed as follows:
(1) Substitute one new tube for one original
tube. If the equipment does not operate,
(1) Remove the suspected tubes one at a time
remove the new tube and reinsert the
and substitute a new tube for the tube
original tube.
Continue this removal-
removed. Note the socket in which each
replacement procedure with each original
tube that is removed was installed originally.
tube
until
the
equipment
operates
Check the operation of the equipment after
satisfactorily.
each substitution. When the equipment
becomes operative, discard the last tube
removed before the equipment became
operative and leave the substitute tube
installed in its place.
*This bulletin supersedes TB SIG 312, 30 April 1957.
TAGO 6224A-Sept. 650575-62
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