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T.O. 31R2-4-101-1
SECTION II
PREPARATION FOR USE
Section II
Paragraphs
2-1
to
2-9
2-1. UNCRATING.
2-2. Carefully remove "the receiver from its shipping
container, using the following procedure:
a. Remove the two steel straps from the wooden case.
b. Remove the cover nailed to the case.
c.
Remove the excelsior from around the cartoned re-
ceIver.
d. Remove the cartoned receiver from the case.
e. Remove the waterproof tape from the folds of the
waterproof paper wrapped around the cartoned receiver,
and remove the waterproof paper wrapper.
f. Open the carton and remove the inner carton con-
taining the receiver.
g. Remove the vapor-proof bag from around the inner
carton.
h. Unflatten the corners of the inner carton, open it,
and remove the silica gel.
i. Remove the wood frame from the carton, and the
corrugated interiors comprising two side pieces, one
front, one back, and one top, each accordion folded.
j. Remove the receiver and set it out of the way in a
convenient place near its final location.
k. Put all packing material in the wooden case and
store.
2-3. INSPECTION.
2-4. When the receiver has been removed from its
shipping container, carefully inspect it for any signs of
damage that may have occurred in shipment. Inspect the
front panel controls, the tuning dial windows, and the
meter for any defects. Inspect the tubes to make sure
that they are firmly seated in their sockets and that
none are broken. Inspect the fuses in the fuseholders on
the rear apron of the receiver to make certain that fuses
of the proper ratings are inserted in the fuseholders.
2-5. REPLACEMENT OF DEFECTIVE PARTS.
2-6. ELECTRON TUBES. If defective electron tubes are
discovered during inspection, replacement must be made
before operation is attempted. To replace defective elec-
tron tubes use the following procedure. (See figure
2-1.)
a. To remove electron tubes V17 and V19, the top-
hat-type tube clamp must first be removed. To remove
the clamp, press inward on the spring, while lifting the
clamp off the tube. Remove the tube by drawing it out
from its tube socket. Replace the top-hat clamp by seat-
ing it on the top of the tube so that the vertical bolt
ad jacent to it can be threaded through the hole in the
spring, with pressure providing a ratchet motion until
the clamp is firmly seated in place.
b. To remove electron tube V4, loosen the knurled
screw holding the tube shield. Then turn the tube shield
counterclockwise, while exerting inward pressure, and
remove the tube shield. The tube is of the pin type and
is removed preferably with a suitable tube remover.
c. To remove any electron tube other than V4 V17
or V19, first remove the tube shield by twisting
c~unter~
clockwise while exerting inward pressure. All tubes ex-
cept V17 and V19 are of the pin type, and are preferably
removed with an appropriate tube remover.
2-7. FUSES. To remove either the 1.6-ampere fuse or
the o/s-ampere fuse, located respectively in the "LINE"
fuseholder (11, figure 2-2) and the "-B" fuseholder
( 1) on the rear apron of the receiver, press in the top
of the fuseholder while turning it approximately 45 de-
grees in a counterclockwise direction. Removing the
pressure in this position will release the fuse which is
spring-clamped to the top of the fuseholder. The fuse
and the top of the fuseholder may now be pulled apart.
To replace either fuse, follow the reverse procedure.
Be certain to use fuses having the ratings speci-
fied above. Use of any other fuses may result
in damage to the receiver.
2-8. SETTING UP THE RECEIVER.
2-9. POWER
TRANSFORMER
CONNECTIONS.
When shipped, the power transformer primary tap of
the receiver is connected to operate from a 50- to 60-cps,
117-volt, a-c source. If the receiver is to be operated
from other than a 117-volt source, change the primary
tap. connection. Table III shows the a-c source voltage
ratIng of each of the primary tap terminals, which are
TABLE III. POWER TRANSFORMER
TAP VOLTAGE RATINGS
Tap No.
Voltage Rating
2
95
3
105
4
117
5
130
6
190
7
210
8
234
9
260
7
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