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 Post subject: 210 filament.
PostPosted: Aug Mon 04, 2008 3:46 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 1690
Location: Eagan, Minnesota, USA
How bright should a 210 tube filament glow? I picked up my first radio with this type of tube, and it seems to almost glow like a light bulb. It also lights up quickly. Is this normal?


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 Post subject:
PostPosted: Aug Mon 04, 2008 3:55 pm 
Moderator

Joined: Jan Thu 01, 1970 1:00 am
Posts: 36893
Location: Livermore, CA
Hi Frank

Bright, a 210 is an early version of a 10. It has a thoriated-tungsten filament which operate on 7.5 volts @ 1.25 amps. Filament type tubes light quickly.

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Norm


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 Post subject:
PostPosted: Aug Mon 04, 2008 3:58 pm 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 1690
Location: Eagan, Minnesota, USA
Thanks Norm. I never had anything with this type of tube before, and found it unusual. Well, just proves you can learn something all the time!


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 Post subject:
PostPosted: Aug Mon 04, 2008 5:55 pm 
Silent Key

Joined: Jan Thu 01, 1970 1:00 am
Posts: 34326
Location: Sandpoint, IDAHO 83864
I have a genuine UX210 large globe style one that tests as brand new and at 7.5 volts on the filament it is all as bright as a small light bulb. Later ones I have are not as bright.
Curt

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Curt, N7AH
(Connoisseur of the cold 807) CW forever!


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 Post subject:
PostPosted: Aug Mon 04, 2008 7:02 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 12615
Location: S. Dartmouth MA 02748-1225 USA
Guys,

Thoriated filament on the early versions of the 210. Very earliest had all electrodes through the press. Soon was learned of leakage in the press at high frequency and voltage. The plate exits through the side of the inner stem.

When they go flat from abuse, at least as long as some thorium is left in the tungsten, they can be rejuvenated.

If you think their bright at 7.5 volts you should see them when flashed!

Later 210's have a oxide filament, a dull red. Later cousins, intended for R.F. have the thoriated filament.

I have a RCA 28 w/104 Thomcat, I've got a bright emitter 210 in the wicker cabinet 104, literally, lights up the room!

I've managed to collect a matched pair and fully intend to build a push/pull crystal oscillator for 80 with them. Yes I HAVE a BIG rock for the rig, could always use another frequency though. Geesh, I hope I don't have to put saw cuts through the base...

Nice tube there Frank, build something with it!

Chas

WA1JFD


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 Post subject:
PostPosted: Aug Mon 04, 2008 8:27 pm 
Silent Key

Joined: Jan Thu 01, 1970 1:00 am
Posts: 34326
Location: Sandpoint, IDAHO 83864
Chas- mine is headed toward a 1929 Hartley as shown in I think the August 1928 issue of QST. High C and the works. Afraid to use a crystal, as they would probably make a good rock crusher.
Curt

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Curt, N7AH
(Connoisseur of the cold 807) CW forever!


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 Post subject:
PostPosted: Aug Mon 04, 2008 10:06 pm 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 1690
Location: Eagan, Minnesota, USA
This 210 came in a 39-A Zenith that plays. Cabinet is also mint.


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 Post subject:
PostPosted: Aug Mon 04, 2008 10:55 pm 
Silent Key

Joined: Jan Thu 01, 1970 1:00 am
Posts: 34326
Location: Sandpoint, IDAHO 83864
Reading some of the old stories in the ham magazines back in the late 1920's and early 1930's will give you some impression on just how popular the '10 was with hams. Most of the tubes were run very hard and way beyond their ratings. Thordarson even had a "210 Power Pack" that was a power transformer, and the filament transformer for the 210 along with another filament winding for a pair of '81 rectifiers. This power pack was supposed to give you 550 volts of pure DC to the plate of the 210 when used with a 30 Henry Thordarson choke and two 2uF filter capacitors. And that was a commercially advertized item, so the abuse of the 210 was somewhat "official", if you can call it that.

Of course there were not many other tubes available for such service back then. The next step up usually involved the venerable 203A, the tube known as the "50 watter". But that is misleading in itself, as the 203A had a plate dissapation rating of 100 watts, but it was a carry-over from the original UV-203 what was only a 50 watt tube.

I would venture that the 210 meant as much to hams back then as the 807 did a few years later.
Curt

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Curt, N7AH
(Connoisseur of the cold 807) CW forever!


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 Post subject: Testing a UX-210
PostPosted: Feb Mon 09, 2009 10:08 pm 
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Joined: Feb Mon 09, 2009 9:56 pm
Posts: 1
Location: CT
Hi Folks

I have a bunch of old tubes I'm testing on my Heathkit TT-1A, but some of the older tubes aren't listed on the "roll chart" or the supplemental sheets. So....question is what can I test an RCA UX-210 as, a "10" as I've seen on some of these posting boards. I've been able to determine that the 210 uses 7.5 volts, and when I use the "10" settings on the TT-1 I get the filament to light up nicely, but it only shows a 500 for a result, whereas a "10" is supposed to test a 1050 reading. It also gives me a "short" reading (as it's supposed to) in the heter cathode test mode on the TT-1.
Any suggestions, folks? Thanks.
:D


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 Post subject:
PostPosted: Feb Mon 09, 2009 10:36 pm 
Moderator

Joined: Jan Thu 01, 1970 1:00 am
Posts: 36893
Location: Livermore, CA
Hi Richard

Be sure you have 7.5 volts at tube pins. A 210 (globe shape) tests same as a 10. It may have a very bright filament.

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Norm


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 Post subject:
PostPosted: Feb Tue 10, 2009 2:42 am 
Member

Joined: Oct Sat 20, 2007 3:36 am
Posts: 14393
Location: Southern NH, 03076
Chas, 80M BC-610 crystals show up fairly often. I have 4 for down in the 3510-3550 range that Ive run serious current thru. They also show up in higher frequencies above 3600.

Carl


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 Post subject:
PostPosted: Feb Tue 10, 2009 2:23 pm 
Silent Key

Joined: Jan Thu 01, 1970 1:00 am
Posts: 34326
Location: Sandpoint, IDAHO 83864
Carl- yeah, do you have any for 3885kc?


The early UX-210 tubes had what appears to be a thoriated filament and they lit up like a light bulb. The later ST shaped 10's seem to have an oxide filament that only glows red.

Since it was such a popular tube with hams in their transmitters, the manufacturers cashed in on it and developed the 10Y, which was officially considered a low power "transmitting" tube and the Signal Corps adopted it as the VT-25 and VT-25A tube, the only difference was the low loss base and the VT-25A met more strict parameters so it made a better oscillator tube that maintained dial calibration better in the BC-AS-283/483 aircraft transmitters which were the for runners of the famed Command Sets (SCR-274N and An/ARC-5 sets) that came along later.

The 801 and 801A are also transmitting versions of the 10, but were mainly for commercial use, but some military sets used them, like the BC-223.

Like I said before, the 10 was to late 1920's and 1930's hams as the 807 was to hams in the 1950's.
Curt

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Curt, N7AH
(Connoisseur of the cold 807) CW forever!


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