Hi I'm Larin Parker with Expert Village and I'm going to talk to you about how to repair circuit boards if you actually have damage to a circuit board in a musical instrument or amplifier or other piece of equipment. Here we see there?s an area where the circuit board has been scratched up. I can tell there would be problems probably connecting this trace. If you look at the circuit boards, you need electricity to flow from these shiny green areas and connect from point to point. We have the solder points here and you can follow the traces and anywhere that you have a crack, this is the same treatment we would give it if we had a crack in the circuit board. You need to just make sure that those traces connect up electrically and you can test that with your multimeter if you take your probes and you test on either side of the problem, you can connect one up over here and connect the other up over here and you have it in continuity mode, it would beep if I had a connection, but I don't have a connection because of the damage to this circuit board. I'm going to go ahead and just fix it up a little bit. The first step is, I'm just going to use the file on my leatherman here, and you just kind of gently file off the top plastic layer, this also helps to clean it a little bit and expose the metal, because the solder won't stick to this green stuff. Solder mask it's called it'll only stick to the copper trace underneath. Then I can fix the copper trace which has been cut but just taking some solder melting it to the tip of my iron there, and then bridging that gap with a little bit of solder. Just tinning it across there until the whole thing is nice and shiny with some solder on it. Sometimes you have to kind of move it back and forth and at the place where there?s a gap, you?re probably going to need to add a little bulbous piece to bridge in that area. Now let?s check out our multimeter and if the circuit board is actually cracked or broken in half, the first step is actually going to be to glue it. I recommend using just a little bit of epoxy; sometimes if it's a small crack you can use super glue. Then file off the remaining glue that seeped through so you can actually get to the circuit area. Now I'll check it out and see if it has continuity and we just check it out from one side to the other and my meter is reading zero so indeed there?s zero resistance. That means that this circuit is now reconnected. With these guys I would l do the same thing, file it back until I see the copper and then leave a protective insulating and some reconnecting coat of solder on the top there.