Inspection; Lubrication - GE BC-375-E Preliminary Instructions

key, place the selector switch on TONE and proceed
to key carrier as in CW.
e. To Increase Power Output:
Go to a higher
number on the ANT. COUPLING SWITCH D at
the same time keeping the P.A. TUNING dial C
and the antenna circuit in resonance. Power may be
increased until a CW plate current of 220 ma at 28
volts input is reached.
To Decrease Power Output.: Go to a lower number
on ANT. COUPLING SWITCH D, at the same time
keeping the P.A. TUNING dial C and the antenna
circuit in resonance.
It should be noted that the CW power output may
be increased or decreased in the above manner from
the value of plate current with the antenna circuit
open to the full load rating of 220 milliamperes.
However, the TONE and VOICE carrier powers
SHOULD NOT BE INCREASED OR DE-
CREASED. Unless the TONE and VOICE carriers
are adjusted as given in paragraph 19d., distortion
will result. Also, the misadjustment may cause arc-
overs which would damage the equipment.
f. To Reset to the Calibration Chart, after changing
of the m-o tube, etc.: Start the radio transmitter on
the highest frequency tuning unit available. Warm up
the radio transmitter on CW key locked for 10 to 20
minutes. The tube shield must be in place. Listen to
the calibrated frequency on a suitable accurate hetero-
odyne frequency meter and adjust the radio trans-
mitter to zero beat by means of a screw driver inserted
into the reset port on the.left front radio transmitter
panel. This should bring the radio transmitter back to
calibration and all other frequencies should be within
0.05 per cent. For greater accuracies reset as above to
the exact frequency desired.
SECTION V
MAINTENANCE AND REPAIR
20. INSPECTION
A thorough periodical inspection of the complete
installation at least once every 50 hours of operation
will materially aid in the maintenance of uninter-
rupted performance. The following inspection is
recommended:
a.
Determine that the storage battery is at the
proper gravity and that the charging generator and
regulator are adjusted so as to keep the battery
fully charged.
b. Clean accumulated dust and dirt from all
units. Use an air hose or bellows, paying particular
attention to the loading coil, item 1170, in the antenna
compartment of the radio transmitter. At this time
inspect the rotating coil in this compartment. The
winding should be thoroughly cleaned using a clean
cloth moistened with naphtha or petroleum spirits.
c. Make certain that all safety wiring is in place,
that all mounting brackets and supports are rigidly
fastened and that all nuts and machine screws are
supplied with lockwashers and are tight.
d. Determine that no cords have broken shielding
and that all grounding and bonding is in place.
e. Inspect plugs for proper fit and plug sockets
for compressed pin springs. Compressed pin springs,
which have taken a permanent set, can be restored by
a light hammer blow on the end of the pin.
f. Make certain that all fuses are held tightly
in their clips. A loosely held fuse should be removed
and the clips bent with the fingers until they grip the
fuse tightly. The clips and fuse ends should be kept
clean and the contact surfaces bright.
g. Antennas should be inspected for broken or
frayed leads, and insulators should be wiped clean.
Be sure that antenna leads have not been bent close
to metal frameworks where high antenna voltages
might cause sparkovers.
h. Inspect keys and microphones for broken cords
and deformed plugs.
i. Inspect dynamotor brushes for length and
broken pigtail leads. Detailed instructions on care of
brushes are given herein.
j. Inspect both dynamotor commutators for
cleanliness and excessive wear. Information on care
of commutators is given in these instructions.
k.
Rotate the dynamotor armature by hand
to make certain it turns freely and is not rubbing
against the field poles or leads. When all four brushes
are removed, the armature should spin freely on its
bearings. Refer to detailed information on dynamotor
bearings.
21. LUBRICATION
a. Materials: The lubrication of the equipment
involves the use of three lubricants and several
cleaning solvents. These are:
(1). Light Oil: A high grade, low pour test, mineral
oil with viscosity rating SAE 10.
(2). Light Oil: A high grade, low pour test, mineral
oil with viscosity rating SAE 20.
(3). Grease: Use only high-temperature ball-bear-
ing grease such as Grade 295, Air Corps Specification
No. 3560. "Lubrico M-21" as supplied by the Master
Lubricants Co., Philadelphia, Pa., or N. Y. & N. J.
Lubricant "No. 1572 Special" are recommended for
use where the temperature does not drop lower than
—31°F. Do not use unauthorized greases as they may
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