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Replacing C299 or UV199 tube - Printable Version

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Replacing C299 or UV199 tube - Jim Dutridge - 03-03-2026

I recently bought a Tri City radio that uses either one of the requested tubes. Looking to purchase 1 or 2 good working tubes.

[Admin edit: This was originally a Wanted Ad but the discussion moved into useful restoration information and the thread was copied to the Electronic Restoration section so it would not be auto deleted (as Wanted Ads are)]

RE: WTB-C299 or UV199 tube - klondike98 - 03-07-2026

If all else fails you might try this fellow's solution. (I have no idea if it actually works or not.)

https://sites.google.com/site/johnengsdeadtechrescue/photos/john-s-ideas-to-restore-dead-technology/restoration-idea-10-uv-199-replacement-for-1924-rca-ar-812-superheterodyne-radio

and here's a CK5676 for sale
https://nesstone.com/product/raytheon-ck5676/

RE: WTB-C299 or UV199 tube - morzh - 03-07-2026

Ingenious. I wonder if there is a way to cut the envelope and glue it over instead of the dropepr bottle.

RE: WTB-C299 or UV199 tube - MrFixr55 - 03-08-2026

The above link is to John Eng, who has a wonderful website.

I would think that it is possible. You will need a blowtorch. I remember creating glassware in either High School or college chemistry.
1. Remove the base
2. Obtain a glass tube, heat the tube and the bottom "stem" of the tube. When both melt, touch together to "weld" the 2 parts together.
3. Rotate the tube heating the seam between the stem and envelope of the tube. When sufficiently hot, remove the stem and "firepolish" the envelope.

Alternatively, create a glass cutter using a length of nichrome wire suspended and powered.

If the getter changes color, rinse it out and paint the interior with silver paint.

Glue the envelope over the base after wiring the submini tube to the base and verifying operation

RE: WTB-C299 or UV199 tube - morzh - 03-08-2026

Will the vacuum inside the envelope not interfere?

RE: WTB-C299 or UV199 tube - MrFixr55 - 03-08-2026

Oops.

Cut the tip off the stem, to vent the tube. then do the above steps.

RE: WTB-C299 or UV199 tube - Arran - 03-08-2026

Another option is to use a later 3 volt battery tube like a 3Q5, and connect it as a triode rather then a beam power tube, this is basically where you tie the plate and screen pins together. I'm not sure of the interelectrode capacities verses a UV199 though but the tube manual will give some guidance, all it would take is a small 4 pin to octal adapter, or loctal if you prefer a loctal version. At least a GT or G style 3Q5 will look somewhat like a 199, without trying to make a fake envelope, which gives them the look of a fake tube amp from the "Middle Kingdom". UV199s, whilst not as common as 01As, are not like WD11s where they will fail if you look at them sideways, resoldering the pins on an existing tube is also worth a try if it tests poorly.
Regards
Arran

RE: WTB-C299 or UV199 tube - morzh - 03-08-2026

MrFixr

https://www.instagram.com/reel/DVQAjIvgcHA/
https://www.youtube.com/watch?v=-fwUFQuPvfM&list=PLhdY-BSDYa7otWjquAJgLmWHQ4oy4JUlW&index=1


Icon_lol

RE: WTB-C299 or UV199 tube - MrFixr55 - 03-10-2026

Hi Morzh,

Attached is another pic from John Eng's site.  Unfortunately, he does not describe how he cut the stem out of the tube:

   

+1 on Arran's comments.  1Q5s were a common replacement for WD11s, as they are cheap.  3Q5s should be similar.  I had several articles on this in the past but can only find one, here:
.pdf WD11 Substitutes DK Owens.pdf Size: 1.46 MB  Downloads: 149


In TRF sets like an Aeriola Sr,  Radiola 2 or a Radiola 3 (converted for 3V tubes or the 3Q5s wired for 1.5V), the interelectrode capacitance differences likely are not an issue.  For superhets, this may be an issue.

RE: WTB-C299 or UV199 tube - klondike98 - 03-10-2026

Because the Wanted Ads will eventually be automatically deleted I am going to copy this thread to the Electronic Restoration section so that it will remain on the site for future folks to be able to search and retrieve it.

RE: Replacing C299 or UV199 tube - morzh - 03-10-2026

MrFixr

I suspect that the problem will only be there if the glass is simply softened: it will start sucking the soft part in.

But I think the vacuum is not enough to really create an explosion if neatly scored.
So if you try one turn of some hot wire, or maybe both this and dip an cold water afterwards, or scoring first...something might work.

Now that I think about it, of you break the tip (neatly) the rest of the envelope might hold just fine. Then the rest could be dealt with.

RE: Replacing C299 or UV199 tube - MrFixr55 - 03-10-2026

Hi Morzh,

Yeah, if yo carefully cut off the evacuation tube , you will vent the tube.  Amazingly, the getter did not change color, unless he cleaned the inside and coated / painted the inside of the tube.

RE: Replacing C299 or UV199 tube - Jim Dutridge - 03-14-2026

I went and ordered a 5676 tube which according to the USPS should be here on Monday (I'm not holding my breath on that). We'll see how well it works.