As we have a thread on soldering I thought it could be good to have one on desoldering too,as I personally find that to be more of a pain. Was going to desolder the CPU from a NES once and when I was almost finished I slipped with my tools and cut a few traces and really messed up the board =/ So any tips on desoldering?
For the cleanest job the best way is to use a backheater and let the parts drop from gravity. Other than that, next best is a vacuum desoldering pen, then a well fluxed joint with a solder sucker, then a braid...
I like using a solder sucker, it costs 3 or 4 euros and it does quite a good job. I used it for making a Neo Geo conversion cart and the results we're great, just be concentrated and when the solder melts, wait 0.25 of a second and suck it, don't let the iron on the joint for 3 second since the trace could fuck up if it's an old board. I don't like the desoldering braid, it's smell gives me headaches, I can't get it to suck Sn+Pb correctly (I don't know the english term for estaño anyway), and I always lose the damn roll!
If you have nothing else, a decent size multi-strand copper wire can be used for simple jobs. Just strip the wire and place over the solder point and press the wire down gently with the hot soldering tip and the solder should start flowing onto the wire when it's hot enough. It only removes a little at a time, so you will have to keep putting clean wire on it until enough is gone.
Use a rework (desoldering) station! Yes, I know they are expensive but they are really the only way to go when you're removing complex devices with lots of pins (i.e. chips) - you want to have a minimal heat time to prevent damage to the board and components, and heat all pins at once, then lift. Whilst the pro ones run into the thousands of pounds mark, you can get the more simple stations for £100. For light stuff, then a solder sucker is quite good. They're great once you have removed a component for totally cleaning the pad - hold the sucker on one side of the board, heat the solder on the other, and suck away! Desolder braid is more for cleaning than anything else - it can't be used reliably on components. If you really MUST desolder the amateur way, note what components are nearby and how much heat they can take! Use a heat shunt on sensitive components. Use a pair of pliers - heat a leg and move that side of the component. Devices with more than 2 legs such as ICs and connectors can be much more difficult to remove. If you're going to keep doing this, you should seriously be investing in the proper kit.
http://www.radioshack.com/product/i...origkw=desolder&kw=desolder&parentPage=search That's what I had (no idea where it is now...haven't done any projects for a while) for desoldering along with desoldering braid.
For surface mount it has to be a hot-air rework station - get it warm enough that the solder flows, then just pick it up with a pair of SMD tweezers A bit of wick cleans it up afterwards. Removing old DIP chips is a pain. Some combination of braid, solder sucker and patience works for me, or if you don't want to keep the chip you can cut all the pins down both sides, then remove them individually by heating them and pulling with pliers. Stone
Removing DIL chips is a piece of cake, just desolder the pins and get it out, BUT you must have care and check that no leg is still soldered, all them must be able to move. If not you'll pry a pad.
Most of the problems I had were with hacking the Jaguar - Atari used massive ground planes with no thermal relief to the pads, so you have to get the whole plane up to temperature before the solder flows. Reattaching the cartridge port on a JagCD was a nightmare, even with a vacuum desoldering station! Stone
Depending on pin pitch, and number of pins (and your patience), you could use a soldering iron with thin tip. I had a video of this method used for removing the RAM chips from an Xbox 1 board (with another video showing how to solder them to another board). For something more crowded though (and therefore small pin pitch), such as a PS2 board, a rework station would work better for better control. Edit: Seems he put those vids on youtube: http://youtube.com/user/stilts07
Practice, Practice, Practice!! The best way to learn how to desolder, is to get a desoldering kit of your choice, then just find some broken or junk electrical item in your house or at a flea market, second hand store etc, and practice on the thing. Old motherboard's, and things like that are perfect, something with lots of chips, and small solder joint's. Once your skills improve and you are confident, then take on whatever you want to do. Also never apply too much heat when desoldering or you'll likely fry what you are trying to lift off. It's somethig you need to practice and get good at before atempting expert mods, as generally some solder goes astray when chipping machine's like the ps2, or any mod with alot of solder, and once you learn how to desolder there is no panic when this occurs.
