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Philco 38-116 started testing tubes - Printable Version

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Philco 38-116 started testing tubes - louxwe - 02-28-2015

So. I bought this cheap tube tester test the tubes on my 38-116, this is just a cheap one to test for continuity but could it be used to test for more?
https://www.flickr.com/photos/58236519@N00/16482486319/
It is a a model FT435. I just plugged them into the octal port and then turned on the power to see if the lights lit up... does anyone know what the other red and black wires are for? Are they hot, how would you use them, I just left them alone.

So most of them seemed to light up fine, but as you can see a couple of them just barely lit up the lighthttps://www.flickr.com/photos/58236519@N00/16482485859/in/photostream/
and it seemed to flicker a bit, two tubes did this. But most of the tubes looked very bright when plugged in like thishttps://www.flickr.com/photos/58236519@N00/16642701416/in/photostream/

There was one tube that felt like the tube part was kind of separated from the black base and it kind of wiggled and spun around and you could here like wires moving sound so I figured it would be shot but when I plugged it in the indicator light shinned brightly.... But I really don't think I should put it back in, it feels like it was going to fall apart anytime.
https://www.flickr.com/photos/58236519@N00/16048701153/in/photostream/

I know each tube is different and probably has different outputs but for the two tubes that barely lit up, is it safe to assume that they need replaced or is this common. All of the others varied in indicator light intensity a little bit but they were all pretty bright. So any thoughts on should any of these be replaced.

Also one of them seemed like the plug on the chassis was a bit wiggly.

RE: Philco 38-116 started testing tubes - codefox1 - 02-28-2015

Well, looks like you have a filament checker, and kykes, depending on the characteristics of the particular tube (filamen voltage) the light may be feeble or bright. You can do the same thing if you have a $10 digital volt-ohmmeter by checking the appropriate filament pins for continuity.

Tube information here for just about anything you are likely to have:
http://www.nj7p.info/Tube/SQL/Tube.php. Pin diagrams are shown from the bottom of the tube and numbers increase anti-clockwise from pin or gap locater.

Nothing else (shorts, emission, even lack of vacuum) will be known by checking filament continuity, but if the filament (or heater is open it is a dud.

Tube sockets can sometimes be cleaned up and carefully retentioned so as to make good contact with tubes. Likewise tube pins can be cleaned off and scraped if need be. Careful clening tubes, sometimes the identifying number is a decal which can wash away. So proceed methodically, and re-label tubes with a bit of tape if need be.

As for a loose base, it is sometimes possible to glue it back together (I use Elmer's, let it soak in for a minute, invert tube in a can or whatever, leave for a week, scrape any glue runs that seep back down in the glass, and test with a reliable full function tube tester before even thinking about using in a set.)

Hope this helps.

RE: Philco 38-116 started testing tubes - K7Sparky - 02-28-2015

In the way back machine we used to reglue the bases fairly often. The old brown glue came loose and I have been trying to remember what the "Old Timers" of the 60s had us using for cement. Might have been water glass. Might try Google.

Some times we soaked the bases loose, desoldered the pins and put back together to get a different configuration or separate wires if multiple elements were on one pin. Don't remember what the tubes we soaked were or what we were reconnecting. Some brands were possible others hooked inside the bottle. Probably for a low power transmitter. Also some tubes were the same as others except the pin out.

Don't know where you live, but try to find a local ham club or Maker group. Someone may have a tube tester and help you out.

A tester will give you a good indication that the tube will work, but the only way to know is try it. If you have ones with the same numbers they may work if swapped.

As Codefox says use a sitcker or a sharpie to label the base as the numbers and letters dissapead easily.

If they are hard to read, cool the tube if necessary and a slow breath out of the mouth on the bottle to fog it will sometimes help bring out the writing.