21FJP22 dud keep or toss?

[Eric H]

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?

[Big Dave]

Hang on to it. It could be rebuilt.

[blue_lateral]

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

[Chad Hauris]

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.

[smoker76]

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

[Eric H]

Originally Posted by smoker76

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.

[smoker76]

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

[Eric H]

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.

[kx250rider]

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

[smoker76]

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

[bgadow]

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.