Electrolytic Capacitor Removal NO Desoldering Required

Hello and welcome to Mr. The Carlson Lab in this Tuesday Tech Tips episode I'm going to show you how to remove surface mount

electrolytic

capacitor

s without

desoldering

them, so let's get started. I am replacing the surface mount

electrolytic

capacitor

s on the acquisition board of this old Tektronix oscilloscope and am often asked how to remove these old capacitors. It's really hard to get them off and yeah what happens with these things is they leak their electrolyte from the bottom and it floods around the pins and makes the solder connections on the board I don't want them basically solder D or even take new solder, it almost sits like a barrier on top, so there is a brute force method to remove them and of course, if you're going to do this, you need to really assess the area.

You know that if your electrolyte has eaten away at the circuit board and you feel the traces are brittle, you probably don't want to use this method, but it is effective for many other

removal

s and you already know that. other boards too and this board here is in pretty good condition when you solder them, you can actually smell the electrolyte if it really has a horrible smell when you solder them, so the idea of ​​using this brute force method is to keep the dwell time of your welder in these joints is less. These things, you know, have been floating around in this electrolyte for quite a while and you really don't want to find out more dwell time with your soldering iron on those joints than you really need. to the right because you don't want to remove any traces and if you do you know you're dealing with the issues well, so if you're going to try this method you'll do it at your own risk, it works pretty well for me. but you know you need to measure what you're doing, it's very simple, all you have to do is go in with your pliers like this, grab a corner of the capacitor and just twist it and it cleans up to see that the joints are absolutely fine on the board of circuit you move on to the next one just give it almost a full circle and they will come off now it doesn't remove the traces on the plate which is a good thing you can see it just comes off and I find this works very well with these older telescopes just like that and now there's no need for

desoldering

, no need for a heated tool here or anything like that, once you've removed all the old capacitors this way.

Now is when you spend your dwell time, so what you want to do is clean the area. I use lacquer thinner, so clean the area really well, apply some flux and some new solder to these joints so they harden pretty quickly, and then. What you need to do is whether you use soldering wick or a desoldering tool. I have a desoldering tool. I just vacuum up the solder and you have nice clean traces and you are ready to install your new capacitors and now you have minimal damage to your circuit board. You'll notice on these boards they have a little positive marked here, so I know which way to install the capacitors.

If you are going to do this, you should first take a photo of your board and you will know if you are doing it. This on a different element or something, you should always take a picture of the board to know which side of the capacitor is negative. Now they mark positive on the board, but on the actual can the little black line is negative, so in a case like this, where the positive is on this side, this capacitor would fit like this, if you're going to replace a lot of these with tantalum capacitors like I'm doing, it even gets more complicated, the line on the tantalum capacitor that Look, here's a line that means positive on this capacitor, so when you're dealing with tantalum capacitors almost always the line means positive When you're dealing with an electrolytic capacitor almost always the line means negative, okay, so here we go, let's see how quickly we can remove these capacitors and prepare them for the new ones.

Note that I'm doing this around the camera. I'm just removing the old legs. See a little leg there. I'll remove it in a moment. It usually stays stuck. the tip of the iron and sometimes they don't and then once that's done I add just a little bit of flux, a piece of plastic that's left there and that's all I do is get some lacquer thinner Kito cleans the surrounding area just to make sure I get all the junk out of the board, there's something that leaked into the board and forget about that little piece of foot left there, here we go, it's out of there.

Now add more flow again, just a little touch on each one like this. and now I'm ready to install my new capacitors just like that quick, here's how I install the new capacitors to make sure there's a good amount of flux on the board. I already did this. I'll just add a little. a little more because it is more or less installed. I wasn't actually going to do this on the camera, so I put this capacitor on it and cleaned it off the board, so we made sure there was enough flow there before. so make sure your tip is a little bit wet so put some solder on the tip of your iron and really all we're doing at this point is just holding the capacitor down so line it up square with the pads and then just tap one side and that's all you really do, okay and then place the next one on the pad making sure you have the correct polarity.

Remember the line on the tantalum capacitors is positive now, if you are reading the ratings on them you are probably seeing that you are crazy, those are only rated for 20 volts and the other capacitors that even those were installed were thirty five. I'll let you in on a little secret: the maximum voltage on any of these capacitors is about 15 volts, so 20 volts is absolutely fine, these two here excluded of course, I haven't measured the voltages on those guys yet, but everything Everything else on this board seems to be absolutely fine now there are two different types of caps on this board that I've used so anyway those are nailed on one side so now that I've nailed them on one side what I do is take my monster chisel tip here again with my huge solder and stick them in on the other side.

It's always a challenge to use the biggest tip you can. Find it in the widest weld you can find, there are no problems there. The cool thing about this is a flux when you put it on the board, it's all your solders beautifully, that's it, the capacitors thank you for stopping by the lab today if you enjoyed this episode. You can let me know by giving me a big thumbs up and waiting, there will be many more episodes like this in the very near future, so until next time, take care, bye for now.