[volt-nuts] Update on 720A

Chuck Harris cfharris at erols.com
Thu Aug 10 12:08:51 EDT 2017


I wouldn't expect physical trauma to be the issue, more something
like a metal flash due to an arc, or tin whiskers... Something
like that.

If the feedthroughs were capacitors, I would suspect a metal
migration similar to what is being seen on many older silver
mica capacitors.

I am pretty sure that everything inside of the can is isolated
from the can.  You could try measuring the resistance between
the affected resistor's terminal, and the can, looking for a
high impedance bridging resistance.

-Chuck Harris

David C. Partridge wrote:
>> I am thinking that the resistor leads have to leave the oil tank some way.  Is
>> it possible that the insulator on whatever sort of feedthru has been
>> compromised?
> 
> They are glass (or very similar) feedthroughs, so if that were compromised, I
> think I'd see oil ...   There is no visual sign whatsoever of trauma.
> 
> If I find anything in that area, be sure I'll shout.
> 
> Dave
> 
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