"Jim Adney" wrote in message
...
I recently got out my trusty Heathkit TT-1 tube tester to check a
bunch of tubes that had accumulated here. I've stopped using its roll
chart, because it's starting to show its age, and I assume the roll
chart is not replacable. If it IS, I'd love to hear about it.




this does bring up an interesting thought, not totally unrelated - with
today's inexpensive computer interfaces, why not build/market a tube tester
accessory that would plug into a USB bus - all you would need is one of each
kind of socket on the unit, and a couple of power sources (filament and
plate/bias voltages) - so a set of SCRs to choose filament voltage and apply
it to the proper pins, 4 or four cheap D/As to create the voltages (maybe
with an HV op amp to create higher voltages), and op amps and A/D with a mux
to scan voltages and currents on all the pins of every socket - this would
probably take no more than 50 to 100 parts and a small PC board and you
could have the tube info read from a computer database and have the test
results displayed graphically - transconductance plots, leakage, emissivity,
all those esoteric parameters.

Done as a labor of love, where the NRE is not amortized, it could be
profitable at the $150 to $300 price range - wouldn't this be a good thing?
it would take less space, be more accurate, faster and less error prone than
using a 40 to 60 year old largely mechanical device.


so, who's gonna make it?


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