So - firstly i am posting HERE (not under repair) because i am trying to sort out some problems with an electrostatic panel driver board (for electrostatic loudspeakers) that i have been having some problems with. I do not know for sure that the problems lie specifically with this board but there are definitely things here that require attention.
1. traces under conformal coating appear to be oxidizing or possibly damaged due to HV electrolysis (?)
2. board itself has very poor HV design (look at all the hard right angles on the traces!)
3. a few of the solder joints appear to have had deep pitting (I am assuming due to coronal discharge activity - or possible bad soldering to begin with and joints originally were done as fillets (which as i understand is not great HV soldering technique - one should have 'domed' or 'balled' solder joints contrary to normal low voltage technique to avoid coronal discharge etc) so I have begun redoing joints on the board.
please note - yes the joints look like hell right now otherwise (mostly due to the thick layer of 'corona dope' on the top layer of the board.
Despite the 'not great' pictures (ipad, sorry) i hope the spotting underneath the conformal coating on the traces is visible. It is MUCH more prevalent on the traces leaking up to the 6KV output terminal - which is what makes me wonder if this is due to electrolytic activity (I've seen this kind of thing happening before with 400V tube circuits and leading to the yoke of a CRT).
My thoughts are to remove the right angled sections of the traces, remove conformal coating on all traces and then lay in 20-24 awg copper wire and reflow the new beefed up traces with solder.
what say you? any thoughts? anyone dealt with this kind of thing before?
oddly the picture links do not seem to be working - here are direct URLs
https://photos.app.goo.gl/4U25CHDzFv6ueM876https://photos.app.goo.gl/wBsM9PyqL3NoxGUi7https://photos.app.goo.gl/FpC1DEC2AU9qLaNEA