Cooking murdered neons, failure modes.

To: tesla-at-poodle.pupman-dot-com
Subject: Cooking murdered neons, failure modes.
From: Tesla List <tesla-at-stic-dot-net>
Date: Wed, 21 May 1997 00:06:25 -0500
Approved: tesla-at-stic-dot-net
Subject: Cooking murdered neons, failure modes.
  Date:  Tue, 20 May 1997 11:56:36 -0500
  From:  "Michael Smith"<msmith-at-licor-dot-com>
    To:  tesla-at-pupman-dot-com





  Hello all,

  This is my first post to the list. i certainly hope that i do not
  generate choppy lines, but I am forced by my present situation to use
my
  work lotus notes email account, and I have zero control.

  I read with interest the thread on baking carbon tracked neons and
  reflowing the tar to break up the troubles. I did just that last week,
  but to no avail. As I type this I have a Jefferson 15kV, 30mA hanging
at
  an angle in an oven, removing the tar. This xfrmr has one good side
with
  a resistance reading of about 11k and one bad side with a reading of
30k
  (ohms).

  My question is about carbon tracking and what one should expect to see
  with an ohmmeter. I would suspect that if there were arcing that
caused
  it to lay down a carbon track, I would see the bad side having a lower
  resistance to the case than the good side, having the carbon track in
  parallel with the winding. Since I am seeing the bad side with  triple
  (in most cases) the reistance of the good side, I fear that this is
not a
  case that can be fixed simply by heating and melting tar.

  This leads me to ask if anyone knows the most common failure modes in
  normal neon applications. What do these things usually die of? I have
  several with open secondaries. There is not too much mystery involved
in
  that case, but what of the ones that exhibit this high impedance on
one
  side?

  I have recently picked up 28 neons of various sizes. A few of them
work
  fine,but they are all small, 5-9kV, 30mA. Of the larger ones I have
  several 12kV and 15kV's that have this one side high trouble. I would
  love to be able to repair some of these. I have enough of the
Jeffersons
  that, if I can get them going, I will have a bank of 3 15kV, 30mA's. I
  would like to make the TC with these to begin with.

  I also wonder if anyone has witnessed any picky behaviour out of neons
  with regard to mixing different brands together in parallel. Ideally,
I
  would want them to all be very similar...but are there significant
  variations, even amongst same manufacturer units? Comments on this are
  appreciated.

  Just as a brief introduction, I am Michael Smith in Lincoln, NE. I and
a
  friend made our first (his second) TC 15 years ago and it worked until
my
  beloved 12kV, 30mA bit the dust. (gee, could I have fixed it??) We
were
  not protecting it. Guilty as charged. This time, however will be a
  different story.

  Great list guys...an invaluable resource. But I still connot figure
out
  how you have time to read it all. Makes me glad the other list I am on
is
  going slow. Anyone talk TC on IRC?? If so, what channel/network?

  Michael Smith
  msmith-at-env.licor-dot-com