I was going to ventilate this dud 21FJ but thought I'd ask if anyone wanted it first.

It says "Rare Earth" on it, isn't that the more desirable phosphor?

Hang on to it. It could be rebuilt.

I agree. As time goes on, more of these will continue to get broken because folks now dont know how to move a set without breaking the tube. It will get harder and harder to find rebuildable cores.

John

I have a 21GVP22 that I think has a vacuum leak as the filaments don't light up. I have been reluctant to toss it but I wonder if it can ever be rebuilt if it has got air in it? I can't see any evidence of the crack though.

Is it the one with the dead green gun filament?
If so, I would be interested in buying it.

Is it the one with the dead green gun filament?
If so, I would be interested in buying it.

The red gun is dead and you can have it for shipping if you want it. :yes:

Is the red gun filament out or is the emmision gone?
Has the tube been rejuvenated?
I am probably hoping for too much but I just thought if a filament was out that I may be able to tap and get it to work. Perhaps you tried that. I have one that had one filament out and tons of tapping made it work again. I had the filament voltage up high and allowed a slow cool down of 1/2 voltage for a half hour then 2 volts, then 1 volt for a long time and it seemed to make it so they come on now without tapping.
Also, I wonder if you have a shipping carton for it?
Thank you,
Johnny

Johnny,

This tube was a grade B rebuilt tube that was pulled from a set, probably around 1981 as that is the date on the carton it's in, it's got plenty of use on it considering the amount of black dust accumulated n it.

The heater works but the gun is dead, I tried rejuvenating but it didn't do anything, I suspect it has an open element inside, the blue and green are OK so it's under good vaccum, I wouldn't hope for much with it short of having it rebuilt.

I have a factory carton that I have used before, it's a little dog eared but should work.

I would definitely say to save it. Smoker76 is #1 who spoke for it, I will take #2 in line in case he doesn't want to bother with shipping... Great excuse to come see your collection!

Charles

I really appreciate it but I need one that could be rejuvenated.
I am glad it is going to a responsible person!

I have debated the keep or toss questions on a few tubes. I have a pair of 10BP4s that are used up & a 21FJP22 which went to air. Well, they don't take up all that much room in the attic, so for now they stay. I can't imagine me ever willing to pay for a rebuild but someday? I have tossed some bad 21" bw tubes because I think there will be an abundant supply for years to come.