Hi,
I took the plunge and removed the LOPT and stripped it down as far as possible. The core didn't want to come apart with very mild force, so I left it complete- it shouldn't get in the way of what I want to do.
There was a very thick coat of wax on the EHT winding so I decided some gentle heat to soften it would be helpful. I left it in a small table top oven at about 80 degrees for about half an hour, checking every 10 mins to see if the wax was soft. It got to a point where I could gently remove the bulk of it with a screwdriver.
During the course of two days, I left it soaking in a container of white spirit. This took a while to soften the wax but it did break it down in the end with a little help with a paint brush now and again.
It didn't seem to dissolve anything it shouldn't and the transformer is now pretty wax free. How much is impregnated within the windings I don't know. Whether they were just dipped originally or were pressure treated would determine that.
My current theory is that the problem was mainly due to leakage from the EHT winding to the surrounding air and also to the transformer core dragging the EHT down. A reasonable spark could be drawn from the wax coating anywhere on the winding. So if that is true, then just re- insulating it should help. Any wax within the windings won't do too much harm, if leakage was the only factor.
I searched for something suitable to re- cover the winding in. RS do an 'insulating varnish' which is specified for transformers, PCB's etc. It is rated at 60Kv/mm, so hopefully, several coats with a small brush should be adequate. It's reassuringly solvent based, carcinogenic and comes with a host of warnings on the tin so might be a good product!! I don't trust anything that doesn't contain dangerous chemicals
I've certainly never had much luck with water based products!
This turned up in a huge box which I expected to contain a massive H&S data sheet, but not a word, only packing materials! When I ordered Araldite, it came with 36 pages (I kid you not) of Hazard information!
I will let the transformer dry out for a week or so before varnishing and then it's fingers crossed time
You can see how thick the wax coating was if you look at the metal dome where the top cap of the rectifier was connected- this was below the surface of the wax!
That's it for the moment,
All the best
Nick