17 Jun
2014
17 Jun
'14
3:10 p.m.
On 06/16/2014 01:39 PM, Tony Duell wrote:
I think there are better potting compounds (or potting composts as a mad
friend of mine insists on clalign them :-)) now. Ones wit ha higher
dielectric strenth. So beeswax may not help that much with the reduced
clearances in a transdormer designed for soemthign that will not break
down so easily.
And break doown it may well do. A lot of insulators are not as good as
you might think. I had a problem with an EHT sense resisotr unit flashing
over the chassis (it was part of the EHT regulator in my Barco monitor,
the plastic casing of the resistor unit was cracked it was othrwise OK).
Anyway, I tried mounting it on a cut down blanking plate fora UK
electricl switch/socket box. It flashed tstraight through that. In the
end I managed ot get some PTFE sheet. About 6mm of PTFE was OK... But I
discovered this _after_ the thing has also flasked over to my figners.
30kV is not pleasant...
-tony
FWIW, if the output transisotrs are not fialing
then generally there's
not a lot wrong with the circuit.
I'm wondering if someone's tried repairing a flyback transformer
exhibiting internal arcing by boiling the core in beeswax. This used to
be the practice in the old days...