Mickey didn't actually do this but it seems like a good idea.
B+ flows through the DC input plug on the back of the radio.
To measure it, acquire a new octal tube base via Amazon or from an old tube you can canibalize.
Jumper pins 6 and 7.
Find four half watt resistors with values of 2.2, 3.3, 4.7, and 47 ohms. The lower the tolerance, the better. Solder them in parallel. The total resistance will be very close to 1.000 ohms. Four resistors of the same value will more than likely show the same resistance error since they were probably manufactured together. Using different values increases the likelihood the resistance errors will cancel each other out. If you don't have the given resistor values, find an online parallel resistance calculator (DigiKey has a nice one) and plug in what you do have until you get very close to 1.000 ohms.
Connect the resistors between pins 3 and 4. Attach two test leads with banana
plugs on the end. Warning: there will be 275-300 volts on the plugs
so use care!
If your meter has leads with probes suitable for pin jacks, using them with
some shrink would be a lot safer because you can shrink tube them better.
Plug in the meter and measure the voltage. 0.022 volts on the meter indicates 22 milliamps of B+ current flow.
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Last modified: Friday, 31 Jul 2026