[Milsurplus] Testing 1625s

[DeWitt Clay]

I have found a Heathkit DX-100 transmitter modulator section a good place to test a box of unknown 1625 tubes. Various problems will show up quickly in tubes that can't stand high voltage in the range of 700 volts. I also made an adaptor to test 1625 and 837 tubes in Collins 32V transmitters. Recommend DX-100s require a (.01uF) cap across the mod xfmr secondary or surges will take out one of the 1625s. 
73, DeWitt  N4QNX

From: Ray Fantini <RAFANTINI at salisbury.edu>
To: Ian Wilson <ianmwilson73 at gmail.com>
Cc: "milsurplus at mailman.qth.net" <milsurplus at mailman.qth.net>
Sent: Wednesday, October 5, 2011 9:11 AM
Subject: Re: [Milsurplus] Testing 1625s

Other than using a power tube in its intended circuit and comparing results between a known good tube and unknown one all other test are questionable at best. Mutual conductance tube testers are better than the Emission types that are almost useless but with power tubes there is no substitute for running it under power. I have used TV-7 that for some reason has the reputation for being the greatest tube tester ever, have a TV-10 in the shop now that I use for checking and matching tubes and had some experience with the TV-2 maybe the most complex and confusing tube tester built but today my favorite tube tester is a archaic Weston OQ-3 or civilian model 788. The question is other than if you just want to check tubes and put them up on the shelf why don't you just go ahead and try them in what you're going to use them in and see if they work or not?