Circuit board repair suggestions?

This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
I've got a good sized 110W x 2 stereo integrated Yamaha amp, I forget the model number off the top of my head. Well it's having problems. Looks like maybe a cat got sick on the top of the case or possibly something was spilled right over the rectifier. What ever it was has long since dried but must be causing a very small short over long periods and has now crisped the board a bit between the legs of the rectifier. Is there something I can put on it to stop the shorting? I was thinking the paint on electrical tape stuff or maybe some 30 minute epoxy? Clear enamel nail polish? Maybe there is a product made just for this?

Things that arc generally create a carbon track, and they'll continue to arc until you remove it. Sometimes scraping with a knife is sufficient, sometimes you have to use a burr in a rotary tool and cut right into the fiberglass. In any case, 30 minute epoxy is a good choice. Avoid 5 minute epoxy as the properties of the stuff are pretty poor. Krylon clear plastic spray is also a good coating for circuit boards, and you can easily repair through it.
It's late 80's, Green PCB I think, it's not near the puter and I don't remember off the top of my head. It's also a single large bridge rectifier, raised off the board about a half inch. Doesn't seem to have cooked the board, it was just burnt a bit where it has shorted due to what ever was spilled / barfed (cat?) on it.

After I had cleaned it with cleaner and compressed air the air must have been damp and I think that left enough residual moisture on the board to sizzle a bit when I tried it out right after cleaning. After sitting a few days I tried it again around the same time I posted this and it didn't short at all. I coated everything down there with a coat of 30 minute epoxy for good measure and I think it'll be fine now.

Thanks for everyones help,
carbon tracks burned into the board are not common, but they do happen, even on green fiberglass boards. easiest fix is to scrape it off with an xacto knife. you have to scrape until you get under the track. if it goes more than 1/2 way through the board, use epoxy cement as a filler. if its a fiberglass board, put a drop of water on the board while scraping, it will keep the fiberglass dust from getting all over your fingers (which can cause a painful and invisible splinter if a fiber gets embedded in your skin).
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.