These tubes really need to be in an amp circuit to measure useful power
output. The filaments can test good with an ohmmeter and hipot can show no
conductivity and still have low emission. The fleamarket price is what the
speculative buyer is willing to take a chance with...I have played with
4-1000`s since the early 1970`s and have tested like new looking tubes that
had very low emission and likewise have had very dirty tubes that were full
output. One thing to look for on used tubes (4-400`s,4-1000`s) is the
interior of the plate structure...If sooty or shows a prism look with
reflection from the bottom,the tube has likely been severly overheated and
will probably be low emission...Just reflections from my past experiance
with 4-1000`s For what it`s worth...73, Jim K7RDX..
----- Original Message -----
From: "Dan Hearn" <dhearn@air-pipe.com>
To: "amps" <amps@contesting.com>
Sent: Wednesday, September 20, 2006 7:51 AM
Subject: [Amps] Price Help
> Our club will have several 4-1000A and 4-400 tubes for sale at the
> convention this weekend. All pass an ohmeter test for filament continuity
> and no element shorts. What would be a reasonable price for each type
> assuming appearance shows little use to obvious usage? Used B and W 30amp
> fil choke?
> Tnx, Dan, N5AR
>
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