Semi-depotting as a way of restoring dead NST's

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Garry Freemyer by way of Terry Fritz <twftesla-at-uswest-dot-net>" <Garry-at-NDFC-dot-com>

Well, I had bad luck and good luck this weekend. The bad luck was both of my
12/60 NSTs shorted internally and bit the dust. ;-P

I tried to depot one using the melt out method of putting the nst upside
down over a try with a grate accross and a hot plate upside down on the top.

This just caused Tar to shoot out the bottom as the case isn't solid and it
was too cold out to melt the rest. I turned it over on the side and sloped
it down at a 20 degree angle and layed the hotplate on the top and let it
cook for an hour. Then I turned it over and did the same with the other
side.

I had planned to snip the terminal connections when it all the tar had
melted away but, the tar on the ends did not melt and was holding the
transformer solidly inside the case. So all the tar along the sides and
bottom is melted away.

Apparrently, the short was in the tar that flowed out of the case because
now the NST works again.

So, I submit the above alternative much less messy method of reviving a
shorted NST by melting most of the tar away, there is a good chance of
removing the tar containing the shortage.

It was pretty cold outside. I would probably have been able to melt the
entire mass of tar if it were warm or I had an old barbecque top to lay over
it.


Sundog, I'm sending this to you personally as well as putting this on list.
I figure it might be worth a try. If you get as good luck as I had with this
method, you might end up with some good NST's with only three hours of
cooking and no mess.

The melted tar once cooled was pried away from the NST quite easily and
tossed like rocks into a pile.

I plan to remount it in my case sans the lid for less metal will mean less
interference with the magnetic field of the primary.