[R-390] Tube testers

[Raymond Cote]

I recently sold my 3 TV-7 tube testers. I thought I might find out the differences between the TV-2, TV-3 and the TV-7 since they were all made for military before I do anything else stupid. I also have cardmatic , I177 and a lab tester with about 8 meters and too many switches to twist. These last ones  keeping for now. 
Any one know or have a link that compares the TV series of testers?
I tried google but gave up after 45 minutes. 
Thanks all
Ray

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Limit all politicians to two terms.
One in office, One in prison.
It works: 
Detroit and Chicago already do this.
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