From the course: Learning Soldering for Electronics

Repair a mistake in a PCB

From the course: Learning Soldering for Electronics

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Repair a mistake in a PCB

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- There are two types of people who design PCBs, those that are going to make a mistake and those who have made mistakes. Everyone makes mistakes, even the best engineers. When you're dealing with hundreds of wires being routed in the software, you're bound to do something wrong. And then you get your boards back and you don't want to wait for another revision. You just want to repair the mistake and test it out. And in this video, I'm going to show you how we can change the trace from this pad to this pad, from here to here. It's a very simple process, using enamel copper wire and I'll show you how to do it, so let's get started. Okay, in this example, we are going to assume that this connection, right here, should not be connected to this pad, but should be connected down to this pad. So the first thing you need to do is stop that connection, or kill that trace. And I like to use a heavy duty box cutter to do this, and you might be thinking it's a little overkill, but I really want to cut through the board and I like how there's such a large handle on this that it's easy to make that cut. If I want to be really careful, I might even do it twice. Okay, and now I would go ahead and make sure that that trace is cut and that there's no electrical connection there with my multimeter. Okay, now that we've cut that trace, let's go ahead and repair it. I'm going to tin the two pads that I want to use. One was right here. The other was here and this is just theoretical. And we're going to use copper enamel wire or a magnet wire. And what this is, is copper wire with an enamel coating on it, and that enamel coating keeps it electrically isolated from other components on your board. We have to burn that coating off a little bit. I'll use a lighter here and then here's a good trick. Sometimes when you burn it, too much comes off, so we can just trim it and then you have just a little clean in there. So we'll go ahead and attach that to the one pad that we wanted to repair. Let me turn this board around, make it a little easier for me. Check it real quick. Look's pretty good. Now we'll cut it to length. I'll give it a little extra. I'll use my tweezers to pick it up and we need to burn off the enamel off the other end. Go ahead and get my lighter again. Just make sure enough's burnt off. I think there's enough, maybe a little more. There we go. That looks good. Now with my tweezers, I'll just take this wire and gently bend it into the position I want. Right there. I'll take my soldering iron, maybe add a dab of flux to it. Can never have too much flux. Just a little wiggle, make sure it's secure. Yeah, that's secure. And we've gone ahead and fixed a bad trace on our PCB. And although this is not good for manufacturing, for prototyping this is a great way to save a PCB and more importantly, save time from waiting for days for a new PCB to come. Now we can go back into our software, redesign this trace, and then when we go to production, we don't have to worry about adding any jumper wires.

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