[Boatanchors] testing 0A2 tubes?

[Greg Mijal]

Assuming your tube tester works correctly.
Which brings up an interesting point.  How many of the folks out there 
actually calibrate their "real" tube testers? May explain why so many tubes 
test beyond good and turn out marginal or worse.
I don't feel like I really need a tube tester for the work I do here. I'm 
more comfortable with a substitution process using recycled tubes. Don't 
need an ESR tester either. But that's just me.
Good luck Eugene, I hope you checked the power resistor and voltages in the 
circuit also.
73's
Greg
WA7LYO
in sunny Feenix


----- Original Message ----- 
From: "Eugene Hertz" <ehertz at tcaf.org>
To: <boatanchors at mailman.qth.net>
Sent: Tuesday, December 26, 2006 8:14 PM
Subject: [Boatanchors] testing 0A2 tubes?


Hello all, while trying to troubleshoot a possible regulation problem in a 
transmitter, I decided to test my 0A2 tube in my tester which is an I-177-B 
military thingy.  Apparently, the test it can do is limited and they caution 
that this is only a partial test.  However, the results are bizzare! So I 
thought my tube was bad because it tested around 500 (on the scale, however 
I dont think its micromhos that its reading for 0A2 tubes) but the needle 
would bounce around terribly while pressing the "GAS 1" button. With each 
purple flash in the tube, the needle jumped sometimes to zero. I even let 
the gas1 test stay on for 1 minute or so in case there was warm up involved.

So I decided to buy some more tubes. I bought a bunch on ebay from a seller 
who has VG feedback and said the tubes were used but tested strong.  However 
on my tester, one was nearly a dud (scoring less than 50 on the scale) 
others seemed very weak and "bouncy" while only 2 were "strong >500" and 
stable.

What does it all mean? Is stability of the needle something that is good or 
indifferent? The manual says >200 is good, but is 1000 better than 200 or is 
a tube like this either good or bad with no in between?

Is there a better way to test these things? Should I throw out this tube 
tester and get something "better?"

thanks
Eugene



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