[AMRadio] Old Tube burn in

[Jim Candela]

 Geoff,
   I think the answer kind of depends....
To preserve the tubes NOS rating, then do nothing.If you want to use these tubes, then that is another thing entirely.They take 5v at 10.5 Amperes.
If it were me, I'd check them out in stages.
1.) Make a socket with a 5V 10A transformer, along with variac control. Slowly come up to 5V. If the tube is full of air, the glass will fill up with smoke.
2.) Let run at 5V for at least 8 hours.
>From here, a lot depends on what test equipment you have. Here is what W8JI says concerning 572B's:
https://www.w8ji.com/572B%20tube%20preconditioning.htm

Good Luck,JimWd5JKO







    On Thursday, February 28, 2019, 8:14:52 AM CST, ARS W5OMR <ars.w5omr at gmail.com> wrote:  
 
 I made a pretty decent deal at a recent hamfest - (6) 250TH'S. (4) of which
are still sealed in their original boxes.

I pulled the (2) out of their open boxes, and it appears as if they've
never been twisted into a socket.

Don/K4KYV, at one time, discussed the pitfalls of running filament voltage
too high, or too low, per Eitel-McCullough(sp?) specs.

My concern for these tubes,  after resting for so long, is that they may
tend to be 'gassy'.

I've heard stories about getting the tubes 'hot' enough to reset the seal
on the tubes.

My question is, how much damage could be possibly done to the tubes, if the
filament voltage is ran up to ~6v, for a week or so? Or, is that even going
to be hot enough?  Should I run some plate voltage on them, with no bias
(and no grid drive!) to get the plate blushing a little to get the heat?

Let's discuss

73 = Best Regards
Geoff/W5OMR
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