I know some of you might disagree, but I've acquired some old, used pedals, some functioning, some not, that I want to butcher for parts. Of special interest is an MN3007/MN3101 pair, that would be great for something like a Porkbarrel or a Current Lover. Now I know how to remove a resistor or cap from a board, but do any of you have some tips on removing a soldered-in IC without frying it? Thanks in advance!
Paul
I've done it successfully with the Radio Shack sucking soldering iron thing that has the little red sucker bulb on top. Some pins take a little extra effort to get free though. Sometimes the pins get stuck to the side of the hole with a bit of solder. I've heated the solder and then held the pin away from the edge until it cooled. Used a small tool like a paper clip or something like that to do the holding. Sometimes it's best to just add solder back to the joint and try again with the sucker. Either way, it's tough work and you need to be determined to do it. My major effort was on a MN3005 and it survived.
If they're plated through hole boards it's pretty tricky without a proper vacuum desolder tool. :(
Single sided etched boards are a piece of cake, you need a desolder pump, a hot iron, ideally a heatsink to protect the IC and a short heating time per pin (3-5s). Proper technique is to 'shotgun' the pins, so you're not applying heat to adjacent pins consecutively, so alternate sides. Melt the solder and quickly suck it away. Like Chi_Boy said, if you don't get all the solder out, re flow it with more solder and try again. Just don't overheat it, there is the risk you can wound the IC and decrease it's lifespan or performance. You should aim to completely remove all solder so no stress is put on the pins during extraction, it should just fall out of the board.
You could get a heat bulb and set it up close to the backside of the board. It's a reflow hack guys use for SMD.
Quote from: jubal81 on December 01, 2012, 02:16:41 AM
You could get a heat bulb and set it up close to the backside of the board. It's a reflow hack guys use for SMD.
This sounds like it's almost to easy.... I could then just pick the IC off the board with a set of tweezers?
Another option is an air gun, but you'd need to be careful not to torch the chip. The advantage is that you can get all the legs hot at once.
All the suggestions so far are tried and true ways to get the IC's off the board. A solder sink would be ideal, but if you don't have one the advice so far is correct. I might add, however, that some solder wick or solder braid is very useful in removing old IC's as well. Especially on plated through holes for double sidded boards. You can get it at RadioShack.
As mentioned before, sometimes the pins get stuck with a bit of solder. You can either reflow new solder and use the solder wick (after allowing the pin to cool a bit) or do not reflow with new solder and just touch the pin with your iron and move the pin away from the side that is sticking with your iron and then remove the heat. Sometimes the small amount of solder left can be dislodged using some tweezers and wiggling the pin back and forth a bit.
Good luck!
Jim
Well, thanks for all the tips guys! I'll probably give it a shot tomorrow, I'll let you know how it all went..
Paul
For single-sided boards, I'd just use a solder sucker and go one pin at a time (letting it cool between attempts).
For dual-sided, I'd try a heat gun on low setting. Once you see the solder flow, run a small flathead screwdriver under the IC and gently pry it up.
Man, I'm glad I socket all of my ICs!
Well, I got the IC's out.... And some transistors as well. Now to see if I didn't fry them in the process! I've got a Porkbarrel board ready to go for an MN3007/MN3101 combo, just need some pots and a regulator for the roadrage to test the whole deal.... I'll keep you posted! One thing I learned from this is how to properly use solder wick. I never really got along with the stuff, but now I know how!
Paul
i usually use the solder wick. on smaller ic's i sometimes grab the chip with needlenose and heat one side lift, then the other 3 or 4 go arounds usualy get it. let it cool at times so the heat dont build up
I want to get a blade tip for my iron, I have very difficult time removing parts esp ICs. I have a solder pump and wick but just not ideal for me. Glad you got them out, good job.
C