Filament or “A" Battery.
There are several indications by
which the user may determine that the filament or "A" battery is
becoming exhausted. These are low filament brilliancy, weak
signals, and distortion, the signals becoming less and less
recognizable, When it is found necessary to turn the "
BATTERY
SETTING
"
control up to 10, and the operation of the set is still
unsatisfactory (or the voltmeter, if used, fails to register at least 3.0
volts with the "
BATTERY SETTING
"
knob at 10), the filament battery
is exhausted. When this condition is reached, the 6 "A" cells should
be replaced by new ones.
Plate or “B" Batteries.
When signals become weak with the
filaments lighted properly and other conditions normal, or if
operation becomes noisy, the "B" batteries should be replaced. If a
high-grade high-resistance voltmeter is available, the batteries may
be tested. They should be discarded when the voltage has fallen to
17 volts for a 22 ½ - volt block, or to 34 volts for a 45 -volt block.
Grid or "C" Battery.
Indications of an exhausted "C" battery
are distorted signals and a tendency to howl. The best practice is to
renew the ^^-volt "C" battery whenever the "B" batteries are
replaced.
NOTE
.—All measurements of
"A", "B" and "C" voltages
should be made under "load" conditions; that is, with the Radiotrons
lighted.
Important.
If any difficulty should arise which appears to be
elsewhere than in the Radiotrons or batteries, it is recommended
that the Authorized RCA Dealer from whom the instrument was
purchased be consulted.
Polishing the Cabinet.
Finger marks resulting from handling
the cabinet may be removed by an application of furniture polish
and the finish thus restored. The polish chosen should be a grade
which will leave the cabinet free from an oily appearance. Rub to a
dull gloss finish, using a piece of cheese cloth or other material free
from lint.
22
