[Amps] TenTec Titan 425

[Richard]

>
>-----Original Message-----
>From: Richard <2@mail.vcnet.com>
>To: Steve Thompson <g8gsq@qsl.net>; AMPS <amps@contesting.com>
>Date: 08 March 2002 23:07
>Subject: Re: [Amps] TenTec Titan 425
>
>
>
>
>>>€ The whatever on the anode is 8kV positive or negative.  This is
>>>apparently sufficient to attract or repell the negatively charged gold
>>>melt-balls - and change current flow.  Typically, I see way less leakage
>>>current with negative 8KV.  With air leakage, the current is the same
>>>with either polarity.
>>
>>
>> I should have said ...whatever the metal is on the inside of the anode
>>...... If we have -ve charged gold meltballs, why should they exhibit
>>different repulsion from the gold of the grid compared with the copper(?)
>on
>>the inside of the anode?
>>
>The grid is at 0v.  The anode is at +8kV.  The meltballs go to the anode.
>When the polarity is reversed, the meltballs seemingly head toward the
>base because current decreases.
>--------------
>Attribution failure
>
€  RR

>When the polarity is reversed, won't the meltballs go towards the +ve grid
>and give the same current?
>
€  With pos. 5kV on the anode, some of the meltballs apparently stick to 
the anode insulator where they form a leakage path.  With neg 5kV on the 
anode, thanks to like charges repel, the meltballs apparently head 
through the grid-cage and fall toward the base.  By tapping on the top of 
the tube, more meltballs can be dislodged and moved into the base.  A 
>20:1 reduction in leakage current can be accomplished with this seemingly 
shmuckish technique.  However, if the tube is inadvertently inverted, 
some meltballs move back to the anode insulator and anode-grid leakage 
increases substantially.  
-  The tapping process also dislodges gold meltballs from the strontium 
and barium oxide emissive coating on the cathode.  Since gold poisons 
electron-emission, dislodging gold from the cathode increases emission.  
Thus, a tube that was producing low anode-current, may return to normal 
emission.  (note - gold meltballs are too small to be seen with a 
magnifying glass, so I use a 30x microscope to view them)

cheers, Steve

-  R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K, 
www.vcnet.com/measures.  
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