[Amps] AL-1200 Questions

[R.Measures]

>On Thursday 27 November 2003 06:26, R. Measures wrote:
>snip
>> >>
>> >> **  When I see gold meltballs through a  microscope, I see no barium
>> >> oxide or strontium oxide.
>> >
>> >I'd be surprised if it was there in large enough lumps to see.
>>
>> **  I can see their spherical shape only with 30 - 50 X magnification.
>> Otherwise, they look like yellowish dust.  [see Fig 24 on my Web site].
>> I can see the cathode coating, but none of it appears to be on the
>> meltballs.
>> --  ¿Why would strontium oxide and barium oxide be attracted to a
>> positive charge.?
>
>I think they don't need to be. If something delivers enough energy to spray 
>melted gold from the grid everywhere, I reckon that it's highly likely that 
>some cathode material gets sprayed around as well, onto the grid and 
>into/onto the gold balls.

**  Could be, however, strontium and barium oxides are definitely 
visable, and saw none other than on the cathode.    

>If I remember my valve theory correctly, that can 
>deliver the 'rectifier' effect and also account for the change in breakdown 
>voltage if the gold balls are dislodged.

**  Most of the gold meltballs I see are not lodged, they're loose and 
free to move around.  
>>
>> >Do you see the effect once the balls are out of the tube?
>>
>> **  I have no means of unsoldering the ceramic-metal seals in order to
>> remove the contaminant.  The most successful thing I have tried so far is
>> moving the gold meltballs down into the base by tapping.
>
>Sorry - I meant do the gold balls themselves show a tendency to be attracted 
>to a +ve voltage when removed in the same way as when they are inside the 
>tube?

**  Good question.  Next time I open a gold-sputtered 8877, I'll conduct 
this experiment.  My guess is that the presense of air molecules will not 
make a difference.
>
>I've been trying with aluminium dust and 20kV, but I haven't yet seen any 
>sign of metal particles being attracted either way.
>
**  One would think that aluminum would behave similarly, although, 
unlike gold, it's outer electron shell is not chock full.

cheers, Steve