Tutorial: My technique for safely desoldering through hole ICs

hi everyone welcome back to Adrienne's digital basement tonight we're gonna have a little bit of a tutorial I'm going to show you my method that I use for removing chips from boards like this this is a Commodore 64 and it's very common you might have to remove a chip as a repair and it's easy if you don't do it right that you're gonna lift traces and caused some damage to the board so I'm gonna show you my method that I've come up with it works for me really well and I know that any time we talk about soldering on a video it's very contentious and I'll probably get lots of angry comments that I'm doing it wrong but this is my method that works well from me if you're looking for tips on how to do this I'm hoping that my method might help you remove a chip from your board easily quickly without causing any damage let's take a look at what tools I'm gonna use to do this so the first thing I use is a desoldering iron these types of things have a regular soldering iron here which on this unit is temperature adjustable and there's a vacuum pump inside any time you remove solder from a board it goes into this little plastic canister here and that's generally how these work this unit which is the s9 93a I got off ebay over two years ago it was a little over a hundred dollars so it wasn't cheap but it wasn't super expensive proper good quality G soldering irons can cost quite a bit more there are some better units that some of the other youtubers are using which may offer better results but this is the one I have and I'm gonna show you how I use this the biggest issue with this unit is because the vacuum pump is inside here there isn't a lot of suction on this and it just doesn't do a good job of getting rid of all the solder you might have better luck with the units where there's an external pump with temperature controls because those use a larger vacuum pump and maybe work better I unfortunately don't have experience with those so all I can speak to is this one so the nice thing about this unit is it came with this nice chunky stand and it did come with an assortment of tips so if you're gonna be removing chips from a board you want to figure out which tip is gonna work work best this one as you can see it's quite large and there's really no way that that's gonna work well on this commodore 64 not on these dips here so the point I'm gonna use is the one that's already installed on here I think it's about a 1 meter unit and it fits nicely over the pin and it puts the heat right onto the pad other things I'm gonna use during this process is some 91% isopropyl alcohol with some q-tips or cotton swabs I use this just to clean up the board after I'm done I use fresh solder to put on to the board as I'm trying to desolder that puts a nice fresh coating I'll show you more about that in a second a chip puller is gonna help and I have a little pic here what I use this for is helping lift the chips up as I'm removing them which I'll get to my technique in a second and I have a little roll of little tape this is simply here to prop up the board I put it on underside and it just keeps the heat from getting down onto my rubber mat the last tool I'm gonna be using is my hot air rework station this one is from China eBay actually and it's very inexpensive SMD rework 8 v 8 has the analog knobs of temperature control and has an airflow control and the hot air comes out of this here the little fan motor is they all integrated it's very inexpensive I think this was about 40 dollars shipped to me so I use something like this and I'll show you how I do it in a second so the board we're gonna be experimenting on tonight is this commodore 64 mainboard has a fault on it so I've already removed some of the chips and I'm going to end up removing one of these 40 pin dips here and one of the RAM chips to kind of give you an example of how to take those out I have always found that 40 pin chips are pretty darn hard to remove so my method works quite well for me and hopefully it helps you as well alright let's get right to it this is the chip I'm gonna be removing from the board it's the MOS 65 10 or the 6502 type CPU that's on the Commodore 64 now to get this chip off we're gonna flip the board over so right away since the back is a sea of green I like to take a sharpie and draw an X in the middle of the chip that I'm going to be removing that way I don't accidentally remove adjacent pins next up we're gonna take my D soldering iron and I'm going to set it for 350 degrees that's why I typically use I don't know accurate this is I find if you're gonna do large ground planes you definitely need more heat but for thin traces on dip board like this single layer board or double air you're going to need as low temperature as you can go well at least as this goes so 350 higher temperatures risk damaging the board even this temperature is a little high I would rather do it around 320 if I could but I can't go any lower than that alright so my technique is to take the tip of the soldering desoldering iron and I put it on the side of the pin and I take fresh solder and I melt it and then once it's melted I put it over the pin and I suck it out so here we go well that was a mistake so let's try again and move it around quickly just loosen that pin up and you sucked the solder out you don't want to hold it on too long otherwise it will damage the board to leave this type this vibrates a lot while your desoldering because of the pump that's in there and it kind of scrapes up the board so I like to go as quickly as possible sometimes you got to clean the tip of the iron off starts to get a little crusty with a lot of solder so just have a little bit of that steel wool stuff clean it off sometimes you have a pin like this one which has a long thick ground and that will wick away the heat so you will have to kind of hold it longer but there we go just holding it on the side with the fresh solder kind of transfers the heat in there gets it melted and then you can suck it right out and clean the tip off all right so now it's time just to kind of quickly inspect make sure that you didn't miss any holes that everything looks good all of the solder is removed at least from this side of the board it looks pretty good now we flip the board over and we're gonna attack the other side all right so it looks like a good amount of the solder has been removed from the top side of the board - but I can see a couple spots like right there that pan is well and one on the other side where it still sort of remelted and what happens is because my D soldering iron doesn't have enough suction is when the solder is melted it doesn't always clean out the hole completely and if you just try to pry this chip up right now it will rip the traces up guaranteed so this is where I bring in the hot air to get this chip out nice and easily without any damage first I take my little roll of electril tape and I prop the board up and again I do this because I don't want the heat from the pins to transfer down into my mat I don't have a very good mat underneath here and it will melt I have my hot-air gun here I have it set for about 360 degrees Celsius and I have the air flow maxed out all the way to number 8 and this heats up very very quickly I have the smallest nozzle on here there are various sizes of the thinnest one so it's the most directed air and what we're gonna do is we're gonna take this little pic here and we're gonna get this just under the chip so I can leave er it out but right now I can tell the chip is stuck in there so I'm not going to apply any pressure and what I'm going to do is I'm going to apply heat around the chip in fact there's a capacitor here I can't really move way so it's just gonna have to survive so I know that there's a couple spots on this side that are stuck and you just gently lift the chip and look at that it's coming right out already so you kind of hook it on underneath the chip there so right there I'm gonna go from this side as well there we go so it's just hanging on by that one pin there we go it's out so at this point it's probably hot to touch but I can just grab it oh it's hot yeah here's the chip it is hot but it's not too hot to hold because most of the heat I was directing towards the legs so this doesn't seem to damage these chips and it gets them out really easily now when we look at the traces nothing was lifted nothing was damaged everything looks good this one pin here which looks like it has a rather thick trace probably it's a power pin for the 6510 so it didn't melt all the solder on the top so we're gonna use the D soldering iron and just we're gonna go over that hole again the rest of the holes look good if you see any that are kind of clogged up you just want to kind of go over them again on the backside with the D soldering iron so let's just quickly do that I can tell it's this pin right here with this little via right there next to it that's the one that's clogged up and it looks like it's clear from this side of the board but I absolutely no it's not so what I'm gonna do is I'm going to take this and I'm gonna take this honor I'm going to apply this sideways onto here heat up the pad apply some fresh solder onto it like there now let's check the other side and it should be nice and clear yep that was it that was the one right there was just with this sick thick trace that was one who's clogged up and it's nice and clear so all of these look really good now so next I take one of these cotton swabs and I apply a little bit of ninety or ninety one percent isopropyl alcohol and we're just gonna kind of clean this up nothing's really on this side of the board looks pretty good because all the extra flux and everything was on this side here so we're just gonna go over this and get that off make this look a little better well so we can take the X off while we're at it so there we go this 40 pin dip came out with very little drama and for me the trick is hot air that does the trick at releasing those few stuck pins without forcing it and without lifting the traces alright just for fun let's remove this Ram chip right here there's nothing wrong with it but let's just take it out and I'll show you how much easier it is to even get these out all right so this is the chip we're gonna do and remember I use the sharpie and just mark it so I won't make any mistakes and let's just get this out alright alright look II mistake so what I did is I removed a solder from this side the right side of this chip and the left side of this chip so I didn't even put my Sharpie mark in the right spot so trap for young player and look I did it as well as I put it in the on spot so I really want to get this chip beer off so let's just do those pins as well so yeah this black mark should have been here where these two traces are that's the row of pins we're gonna remove and the last thick one we go I can't believe it put the mark in the wrong spot all right so that's the chip and now I can see that it's clear of solder on both sides but just like the 40 pin dip this is still stuck in here so we got to use the heat gun I'm gonna prop the board up I'm just gonna give it a little heat because it's so small this is much easier or usually it is yeah if I popped right out there we go right out of there there's the chip came out no fuss no muss I would easily be able to put a socket on there right now or if I want to read could put a chip straight back in the board no problem let's just clean that up get the flux off it and if you make a mistake and you put UD solder half of another chip don't forget to resolder that chip it together before you try using the board or you're gonna have an issue nice clean this up everything looks really nice and clean under here just to fix my mistake I'm gonna I'm gonna restore those pins there well here's a test Commodore 64 that I have and I want to see if the CPU I just removed actually works in here so let's turn this on make sure it's working first thumbs up I got the regular Commodore 64 startup screen this is the CPU right here has two heat sinks here's the CPU I remove from that board and I did spend just a little bit of time cleaning up the pin so just use my soldering iron and kind of wiped all the slag off though so they're nice and smooth now so they should go into the soccer without an issue let's pull this chip out and put that one in and see if this one is working okay there's the old chip out this is the chip we just removed which if it works it's gonna be a spare part for me just line this up there we go power Hey it's functional that's awesome well there you have it I hope you found that helpful in some way I am sure there's gonna be a lot of people who have a lot of things to say about how I did it right did it wrong whatever but feel free to put those in the comments section below I'm always looking for tips but my method of using the Duc de soldering iron even though it's a crappy one and the hot air works every time it's just so easy to remove chips from boards without causing any damage and I'm not spending a ton of money in the process either thumbs up if you like this thumbs down if you hated it subscribe more videos thanks for watching bye

Channel: Adrian's Digital Basement

Views: 102,254

Rating: 4.9341664 out of 5

Keywords: desoldering, commodore 64, c64, vintage computer, through hole IC, DIP IC, computer chips, MOS 6510, retro computers

Id: XQVjwPsVFd8

Length: 18min 1sec (1081 seconds)

Published: Thu Mar 07 2019