So I had a 3x AA battery pack go off inside of a HP8350 generator that I got on ebay, and the solder mask coating on all the thicker traces is screwed up.
When I started to clean up the residue, basically all the solder mask on thicker traces started to come off, and the planes are totally exposed now. (after cleaning it started coming off like sunburn on any trace wider then 1mm, and the traces with battery chemical damage are spotty, but the solder mask adheres better here). Pissed me off so I put it in the dishwasher and then scrubbed the rest off with a soft scour pad, so I have a fairly bright gold PCB. The surface finish is not scratched up. Not sure why only the fat traces are effected BTW. The thin ones are durable as ever, the thick ones just turned into sun burn. But maybe it was contaminated with battery crap , better safe then sorry.
Since its a big backplane PCB and it has connectors soldered to it, I need a conformal coating that I can carefully paint on with a brush. I only don't need to coat a few areas with screw in capacitors and can do some fine work with a thin brush between the connector pins.
The PCB is large, around 2sq feet and has a gold finish. I thought to use a MG chemicals product, but I am not sure what the best one would be. I thought about the 4200UV coating, which is UV triggered.
https://www.mgchemicals.com/products/conformal-coatings/uv-conformal-coatings/uv-cure-conformal-coating/Is this a good choice? I hope these coatings can be put on bare gold finish without having a solder mask...? It is just a interconnect board, there are only some gold pins and cinch connectors on it.
I heard the chinese UV-silk screen is hard to use
https://www.eevblog.com/forum/manufacture/solder-mask/msg2206320/#msg2206320So is strait up conformal coating a better idea for a repair? Or if I don't care about aesthetics, is the solder mask paste good enough for some manual 'don't give a fuck about looks' application? I read gold poses some special problems for solder mask, so maybe just acrylic is better? I don't care if its clear, I just want it to stick to the gold good.
posted this in assembly forum by accident because I was searching it. I also already have red insulating varnish from MG chemicals, but I am trying to choose the best product here, I don't mind spending a few dollars on this one if its
durable.
Not 100% sure its the problem but it looked like it might have been, I don't want to reassemble all this shit without fixing the PCB up, there is too many screws, and I have a sister unit coming in so I can work pleasant doing board swaps.. so repair probability is high and I figure ima just fix everything I find as I go.
Why buy one when you can buy two for twice the price? I already have a strong UV source I made BTW (15W single LED 385nm)
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