[Amps] Question on installing new Amp tube

[Lee]

This scheme makes no sense to me.  It is known a 3-500Z tube has it's 
getter on the plate.  So if you place 45 volts on the plate and draw 400 
ma, you have a plate dissipation of 18 watts.  18 watts is not even 
close to getting the plate cherry red.  In fact it won't get the plate 
to glow at all.  Since the plate is the getter and it can't getter 
unless the plate is glowing, how in the world can this scheme work?  
There is something wrong here.  This scheme is telling us the getter 
works without a red hot plate.  This is news to me as every other 
gettering scheme I have seen insists on getting the plate to glow.
Lee, w0vt

On 8/8/2015 10:59 AM, Mike Tubby wrote:
> If the 3-500Z has stood for a long time unused I suggest you use the 
> 'Reactivation 3-500Z' procedure by PA0FRI, here:
>
>     http://pa0fri.home.xs4all.nl/Lineairs/TL922/tl-922eng.htm
>
> When I did this with a new-old-stock tube I used 40V and had no 
> significant current indication for about 1.5 days, then the current 
> meter started to 'flick' a few milli-amps and back to nothing and then 
> after a few more hours it started a constant reading of around 50-60mA 
> which then rose until it hit my current limit.
>
> I used a pair of 0-20DC bench power supplies in series to get 40V and 
> set the current limit at 400mA.
>
> After the reactivation I put the tube in a PA and it worked fine.
>
>
> Mike G8TIC
>