I'm about to make a purchase of a Zenith Roundie and I'm trying to make sure the picture tube is still good.. He said he tested the tube and the filament lights up as it should, meaning it's hasn't gone to air.. He said he tested it in 35 degree weather and does get response on all 3 guns and got around .2 ma on each gun, cold, and said they should go up considerable if allowed to warm up.. I figured I would get some input..

just go git it! If it don't work you can bury it in the yard...

It's something far away that gonna cost a pretty penny for to have a moving company or something to ship..

Where do you live

I live in South Florida..

Just because the filaments light up doesn't mean the CRT is still good... ask the many 21AXP22 dud owners. Good thing is it's a Zenith so it has a glass tube, making a leaker much less likely. Cold temps will make the guns read low, I think you'll be fine once it sees higher temps.

Ok, thanks for the input...

Hey hope you grab that roundie and wish you lots of luck great score...Timothy

I got the set and comes to find out the original Zenith 21FBP22 is pretty much dead, no emissions on all three guns, upped the filament voltage on the tester to 8 volts only to find out the emissions go up but down as the tube cools to 6.3 volt temp..

Did you let it cook for a while?

Yes, overnight, and it did not improve, not even by the least bit..

What are your plans for the set now?

I'm trying to locate a 21FBP22, hopefully a Zenith, but if not, any make or model substitute will work as long as the tube has great emissions, no shorts, good tracking, and cut off..

i may be listing a couple on you know where excellent emmission rebuilds.

Excellent emission rebuild would be great, do you have one?

What would outside temp have anything to do with something thats in a deep vacuum? .2 ma is deep into the weak zone, 1ma is new. It would produce a dim but usable picture.

You should go for it, they are good sets. You can always find a crt later.

It does produce a picture, but like you say it's very dim, and that's with all the settings up at the highest..