Good enough. I did have a 3-500Z switch tube in my 314R1 broadcast transmitter
go bright yellow on the plate when the clamp diode was shorted across it. The
plate overload saved it but for a moment it was quite bright. There was blue
fluorescence on the glass.
I suspect that the plate outgassed a little, as it was 'processed' higher
temperature in situ than Eimac likely did. It survived this test OK!
> But this doesnt apply to the ham type tubes in service today. A 3-500 doesnt
> outgas at a red color and I havent found any decrease in a hi-pot even after
> an extended bright orange.
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