RE: I wonder ...

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

Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi Garry,

I have always thought ACTown NSTs were built very well...  They talk up
quality pretty heavily and they don't cost that much more new...  They are
sort of rare used.  NSTs that fail a lot tend to show up in the junk pile
more often... 

It seems like the quality of most NSTs depends on the person that was
building them that day.  Some are all screwed up and others are perfect...  

Over the years I have heard both good and bad about Jefferson, Transco,
Allanson...  Then you have to consider how many years it was sitting in a
neon sign at from -30 to +110F temperatures (low humidity too here in
Colorado)...  Then you have to worry about how long the rain and rust
drained into it at the junk yard or in back of the sign shop in the
"pile"...  By the time us at the end of the chain get hold of an NST, there
is no telling what we have except plugging it in and hoping it still works
well enough.  In the case of MMCs, we get those almost always new so there
is not too much that can go wrong and the manufacturers are all known for
high quality in that industry.

If we always got our NSTs new then we would have a very good idea of the
quality differences.  However, there is so much that can happen to them,
despite how well they were made in the first place, that the original
manufacturing quality looses much importance.

IMHO

Cheers,

	Terry



At 10:52 AM 5/30/2001 -0700, you wrote:
>Hi Alan. Well you may disagree but my experience with the 12/60 Jefferson
>was QUITE different than yours and I am not alone in this experience. No
>offense taken or intended, but I don't lie.
>
>I think Terry was one who had difficulty with a Jefferson. Whoever the two
>people who mentioned bad experiences with Jefferson's please speak up! There
>was one who said the layers were tarpaper and also were disolved along with
>the tar. Mine is completely ruined because half of the paper on one side was
>completely disolved away leaving a birdnest of ruined windings. The tar
>resisted desolving like mad. I put the thing in an oven and I set the
>temperature to 200 degrees. After 45 minutes, the tar was still hard as a
>rock. I increased it to 250. Another hour and the tar looked shiney but hard
>as a rock. I increased to 300 for 30 minutes and it still pretty hard. I set
>it to 350 for another  hour and it was just softened a little. I ended up
>setting it up to 425 or so before the tar began to start running. I finally
>got a good portion of the tar out and then I plugged it in to see what was
>up and I immediately got sparks from the windings to the case. The area
>between the case and the windings had no insulation. There was NO tar and
>never was any tar between the windings and the case as the area of the case
>was clean as driven snow and I would think that if there were ever tar
>there, it would be left on the inner side of the case.
>
>I soaked the thing in mineral spirits for two weeks and then looked at it.
>Only the outside surface of the tar had softened and it was protecting the
>inner surface. There were large parts of the tar that were had as stone. A
>month or two later I looked at the unit and the condition was much the same
>with large stone like portions of tar covered in a whitish substance.
>Contrast this with the two Allansons I depotted. They were virtually clean
>in a month of soaking. I soaked this unit from Mid November till the last
>week in April and the tar was finally softened enough to remove with a brush
>but the tar had a fiberous stringy consistancy as if it were full of sewing
>thread. I carefully brushed off the unit under the tar and removed it and
>here was half the secondary insulation eaten away leaving the windings
>sticking out in space.
>
>I'm not particularly concerned about removing shunts. I get quite
>satisfactory performance with the allanson I depotted and besides, its too
>loud already! ;-)
>
>I guess, all I can do is calmly say, that your experience doesn't even
>remotely jive with mine and a couple others on the list. I don't doubt what
>you relate. I'm just a little mystified as to why your experience can be so
>different than mine. The only difference I can see is you used a BBQ and Gas
>and depotted two quite successfully and I used an Oven and mineral spirits
>and I only depotted one. Perhaps it was the extended soaking I gave the unit
>that finally even broke down the paper? How long did you have to soak them
>in Gasoline? How hot do you estimate you had to get the tar to melt? A bbq
>sounds like it could easily get to over 400 degrees.
>