Hickok 539C - Page 3

AUTOMOBILE RADIO TUBES
It often happens that automobiles operated at
night with radio, light, fans, etc., all turned
on at the same time, put such a severe 109.d on
the auto battery that the battery is unable to
deliver full voltage, especially in slow moving
traffic or when waiting for traffic light. If
auto radio trouble is experienced, much time
can be saved by first checking the tubes at 6.3
volts, then switching the filament voltage to
5 volts. If tube reading drops markedly at 5
volts, the tube should be replaced.
If the automobile has 12 volt radio system,
first check the tubes at 12.6 volts, then drop
to 10 volts for recheck.
ACORN TUBES
Adapter, Code 1050-9, is available for testing
Acorn tubes with the 539C.