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Help Identifying A VERY Old Vacumm Tube? Answered

I recently got a 1920's RCA Radiola 60 Tube Radio , and when I was servicing it I kinda accidently dropped a tube and the vaccumm seal broke and the glass broke. on the side of the tube it says "Philco H 5" it has four pins two bigger two smaller. Here are some pictures of it for reference.

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Goodhart (author)2008-09-11

if it is a full rect. tube it might be a T-5AR4-C (or a 5U4, 5Y3, or a 6CA4) ?

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jackillac92 (author)Goodhart2008-09-12

Thanks do you know where I can buy them?

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Goodhart (author)jackillac922008-09-12

I believe Gmoon is correct here (it has been a loooong time since I dealt with many tubes...sorry about misleading)....well there are still a few places left ( I can vouch for none of the following) Vacuum Tubes, Thermionic Valves, Electron tubes...
or Vacuum Tube net
there is Orlando Vacuum tubes
and finally the Antique Electronic Supply
...actually there are many more that a quick Google will bring up....

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jackillac92 (author)Goodhart2008-09-18

Is it a double rect one or the full rect one or single rect?

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Goodhart (author)jackillac922008-09-18

I think he meant a dual diode tube, and since a rectifier bridge is made up of 4 diodes, that would be a half wave rectifier tube, and if there is another, then the combination would make a full wave rectifier.

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gmoon (author)Goodhart2008-09-19

In tube circuits, a dual-diode rectifier is all you need for full-wave rectification. The difference is the transformer, which is center-tapped. A second tube (and socket, wiring, etc.) was more expensive in those days, and a larger transformer with twice the coil wiring was cheaper. You'll see transformers like this speced as 400-0-400, or something similar. It's essentially +400 and -400 in respect to the CT (and you can get 800V if you bridge-rectify the ends and ignore the center.) With silicon diodes costing only pennies, the center-tapped power transformer has disappeared from most modern circuits. Illustration is from wikipedia...

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Goodhart (author)gmoon2008-09-19

Thanks Gmoon, I was unaware of this aspect of the tube (they were disappearing, more or less when I was still young and never fully got to "play" in that area.....I still remember my Dad's first handheld transistor radio, which took 4 D cells and had what appeared to be a metal shielded tube in it :-) It was in a leather case, no less, made by GE, IIRC.

I wish I had kept it and cleaned it up.....the batteries leaked one day and the battery holder became, um, messy.

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gmoon (author)Goodhart2008-09-19

You and I are contemporaries (from what you've written, I'm ~ one yr. older), so we both witnessed the "tail end" of the tube era. I only became interested much later (through guitar stuff.) But growing up, we had a tube stereo console, tube TVs, etc... I remember those early transistor radios.... $59 for a radio with three transistors... :-\

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Goodhart (author)gmoon2008-09-19

yeah, I kick myself every time I think about my throwing it away, when I could have just either cleaned it up a bit in the battery compartment or replaced that piece. I actually found a picture of one EXACTLY like the one I had....

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gmoon (author)Goodhart2008-09-20

Retro cool. I imagine the majority of these are landfill, which is a shame... (BTW, radio nerds are just as fanatical as guitar amp geeks or audiophile wonks...)

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Goodhart (author)gmoon2008-09-20

This was a favorite radio of mine too (actually it was my Dad's but I got to use it most often), and I remember it soo well.....the back snapped open, the flap raised and the radio split in two like a suitcase, and the batteries went into the right side and bottom ( with the back laying face down) and the tuning capacitor was nearly the size of a lime....*sigh*
Should auld acquaintance be forgot,
and auld lang syne ?....

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gmoon (author)Goodhart2008-09-20

Maybe...or maybe you'll find another.

And we'll tak a right guid-willie-waught,
for auld lang syne...

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gmoon (author)Goodhart2008-09-11

I think the schematic is correct (most of the rectifiers you list are newer than 1930):

280 rectifier search on ebay

This image of a radiola 60 shows a similar "bulb" type (old style tube) glass envelop (tube at the top of pic, according to the chassis drawing, NM's link.) Just like the ebay search results. With a bit of imagination, the rectifier tube in the pic looks to have the same structure as the broken tube...and I know that's the internal structure of a dual-diode rectifier (at least the guts look just like a 5U4 I have here...)

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Goodhart (author)gmoon2008-09-11

Oh yes....sorry, those I listed were the ones I was more familiar with....I remember Nixie and magic eye tubes well *sigh*

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gmoon (author)Goodhart2008-09-11

I remember Nixie and magic eye tubes well *sigh*

As do I, and we're becoming as rare as the tubes (LOL)...

(when I was a kid, my cousin worked at Wang labs, and I used to play with the nixie calculators he brought to my grandfather's home in Lowell, Ma.)

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Plasmana (author)2008-09-13

I don't have a clue, I am too modern for this old stuff...

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jackillac92 (author)NachoMahma2008-09-11

Huh I dont speak tubes sorry?

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gmoon (author)2008-09-11

There's two four pin tubes in NachoM's schematic. The rectifier and a power triode (output.) From the remains, it sure looks like a rectifier tube (dual diode.) So I'd bet it's the "280" rectifier on the chassis diagram... Good luck--it looks in excellent shape!

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skunkbait (author)2008-09-11

That's an awesome radio. My grandfather had one like that when he was a kid. He told me about listening to the first broadcast of the "War of the Worlds" on it. Hope you find the right tube!

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NachoMahma (author)2008-09-10

. Maybe a 1H5G or 1H5GT? 2B-H5? 2FH5? 3FH5? 6EH5?

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