Introduction: Fedtro Vacuum Tube Tester to USB Conversion

Picture of Fedtro Vacuum Tube Tester to USB Conversion

Well, I basically took the tester and removed the battery spacers out that were obsolete

Due to the size of the battery which was slightly smaller by a 5th of it. I then took an old Phone usb and usb adapter charger and clipped the micro usb connection off exposing the internal wires I then soldered the negative to negative and positive to positive and ran several test to confirm if is usefulness it worked like a charm.

tested the tester by plugging it into the outlet and computers even my car and it worked :)

so here you go enjoy

a Fedtro Vacuum tube tester circa 1966

To USB Conversion.


robot797 (author)2015-10-15

this isnt a real tube tester

it is a fillament checker

it checks the fillamtents


Democon (author)robot7972015-10-15

Filament Checker Tube Tester

Tester is commonly used including by the maker so yes its a tester maybe not the tester you want it to be but it is a tester. :) thank you

robot797 (author)Democon2015-10-15

i know but i like to warn people about it
becaus i was fooled by it once (when i just started working with tubes)

Democon (author)robot7972015-10-15

To bad the technology is so great even at its age it is so much fun the image you have as your avatar what is that

robot797 (author)Democon2015-10-18

it is my firsth oscilloscope
i got it for free from a co worker
i had to dismantle it affter a year of service
it stoped working

Democon (author)robot7972015-10-19

omg I would work on it if it was mine. I actually had a hughes mitchell VFO i purchased online circa 1939 it was pretty busted up but I fixed it up really nice bought it for 90 sold it for 200.

Democon (author)Democon2015-10-15

is that a vintage oscilliscop? man its a beautiful piece

robot797 (author)Democon2015-10-16


you think that

Democon (author)robot7972015-10-16

cant really tell without my glasses

robot797 (author)Democon2015-10-16

ah that explains

BeachsideHank (author)Democon2015-10-16

You are both right to a certain degree, it is technically a filament continuity tester, the most likely part of a vacuum tube circuit to fail. More electronic circuitry is required to determine gain, leakage, and other useful information about a tube (valve for our Brit friends). My teenage buddy and I used to make these back in the '60's to test tubes from old television and radios we salvaged. For more comprehensive data, we would take them to a local food store which had the big console type tube tester that would check all parameters. I recall we used the venerable #47 6.3 volt mini- lamp as the indicator. That jeweled lens cap is a keeper, they don't make 'em like that any more.

Democon (author)robot7972015-10-15

Thanks for sharing :)

amberrayh (author)2015-10-15

Nice fix. Thanks for sharing!

Democon (author)amberrayh2015-10-15

your very are welcome.

About This Instructable




Bio: I love Technology with a passion its constantly changing on a daily basis. This phenomenon is so overlooked by the most of the world we ... More »
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