[Milsurplus] Mercury Rectifiers

[Bruce Gentry]

Yes, it is an issue- and well known.  Standard practice is to turn on 
the filament only for about half an hour to cook off the mercury in 
places it should not be. The tube needs to be in a warm place, it 
sometimes won't work if the tube is really cold, like an unheated FM 
transmitter hut in the middle of winter. Once the mercury splatters are 
all vaporized from the upper part of the envelope, it should be ready. 
Also, in case you didn't know, the tube must be preheated and operated 
with the base down only. If you lay it on it's side, or shake it and 
splatter the mercury, preheat it again. Once the splattered mercury has 
been cleared, remember to preheat the tube each time you use it for 
about one minute before applying plate voltage, otherwise the filament 
is likely to be damaged and the tube may flash over, or as we used to 
call it "backfire".

  Bruce Gentry, KA2IVY

J. Forster wrote:
> Hi,
>
> Is there an issue with Mercury pooling in rectifiers, like the 866, in
> long term storage that would cause them to blow over more easily?
>
> If so, is there a fix?
>
> Best,
>
> -John
>
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