[R-390] Tube Testers

[Bob Camp]

Hi

The military tube testers are all fine for testing the tubes out of an R-390. Prices are silly high ($200 for a TV-7). About the only time they really shine is when you have a stack of gear that was left on well after the first tube failed. The result can be that 2/3's of the 40 tubes in an instrument are dead (and you have 10 of them to fix by 5 pm …). They also can be a help in confirming what you already know from basic troubleshooting. 

A tube tester (depending on it's design) does not test all the functions of a tube. Most do some very simple tests. An open filament will indeed fail. (Hmmmm tube is cold … hmmm). Past that they give free advice (worth what you paid for it). A tube that tests "good" probably will work (unless it's leaky). A tube that tests "bad" may well work fine for another 10 years. 

A tube tester gives you one more piece of gear to maintain (and calibrate). It's also one more thing to lug around (=why I like the small TV-7). For the money you can buy a many lifetimes supply of all the tubes in the radio. Swapping tubes is at least as good a fix as using a tube tester …. 

Bob
 
On Sep 16, 2013, at 10:03 PM, R. David Eagle <kb8nnu at yahoo.com> wrote:

> Ok all my boat anchor enthusiasts!  I am preparing to restore my first 390A.  My question to you all is what is a good universal tube tester to have around and what would might be a good price? 
> 
> Thanks in advance...
> 
> Dave
> kb8nnu
> ______________________________________________________________
> R-390 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/r-390
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:R-390 at mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html