often if I restore radios I like to do them in pairs so I can swap stuff for troubleshooting. If you are working on an AA5 this might be easier than something more unusual. Ive got a few testers and we could try them but I am unsure of the reliability, so usually I dont; try to sell tubes unless I can help someone. what tube are you trying to test? if it’s somethign common like an 80 I’d just pull one from a working set even just to test with. Not very scientific I know. I can’t say for certain but you could try to take it to the SPARC museum , they may be able to help.
all testers wont; test all tubes, so unless you have a sophisticated tube tester you might have to kind of pair the tester up with the era of the radio, in other words a tester from the 30’s might not check AA5 tubes and vice versa
What kind of a radio are you working on and what is the issue you are having? Im in new west, I might have a working radio that uses the same tube number?
if you just want ot check the tubes for a non working set I would try to do the preliminary checks, measure resistors, compare voltages at pinouts either to the schematic if voltages are given or to specs from a tube manual to get an idea if the things that you can measure are within reason. If you haven’t recapped it and checked resistors I’d generally start there, and then if you still have difficulty look at the tubes more closely. sometimes what I have done is just find a bunch of tubes of the same numbers of whatever set i’m working on.
, then if I test them I try to do them in a group to get a better comparison than just relying on the tester readings. If you can plug them into a working radio then often you can know if they work or not and then perhaps use tester readings to sort out the ones with the best readings.. If you are lucky enough to find someome with a reliable tester, like someone that sells tubes might have a Hickock that will check the mutual conductance etc. In other words find one that is callibrated and in use , then maybe I’d trust those readings more, if it has been proven to be reliable.
. If someone just drags one out of storage the results might be questionable, but comparisons might be less subjective than the actual readings. a lot of the drug store ones would fail tubes which are still good. You can check the filament with a tester , just be aware the tester you have might put out 9V and the filaments of some of the antique tubes are of a lower voltage. might be safet to use a 1 volt battery and then measure the voltage than to set your meter on ohms.. You are probably unlikely to blow the filaments of newer tubes but with WD11’s or other rare antique tubes be careful with that.