On Dec 25, 2005, at 12:27 PM, Peter Chadwick wrote:
> As I understand it, the filament structure is the same as the 3-500Z.
> Not sure about filament to grid spacing,
I don't know the distance involved, but the filament to grid breakdown
potential is typically 6000 to 8000 volts.
> but I have had some go grid to filament short when hot, and that's
> with them mounted vertically. Depending how many tubes you have, it
> could be worth trying. Rich Measures may have some historical
> knowledge of 3-500 failure modes which could be applicable.
In my experiences, 3-500Zs typically fil--grid short at around the time
that a big bang is heard. Applying a short between the grid pin and a
filament pin makes no sound.
> I think personally, I'd avoid it, but that's partially because I don't
> have a lot of spares!
> Peter G3RZP
> Amps mailing list
Richard L. Measures, AG6K, 805.386.3734. www.somis.org
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