Reworking is one of the regular tasks of anyone who is involved in an electronic design process, because try as we might, it’s rare to get a design perfectly right the first time. Some reworking tasks are more difficult than others though, and we have to admit that lifting an IC pin doesn’t always result in success. But with this video from [Mr. SolderFix] there’s hope for conquering the technique, as he takes us through the best pin-raising technique on a variety of packages.
The trick it seems is to lift the pin first without attempting to disengage it from the molten solder, then returning to it with some copper braid to remove the solder and leave it raised. Once the secret is revealed it’s so easy, something a Hackaday scribe should be able to do. He does sound a note of caution though, as some packages are prone to disintegrating when stressed. A broken SOT-23 is not something anyone likes to see through their magnifier.
His channel is full of such no-nonsense soldering advice, and should be a fascinating browse for many readers. Meanwhile we’ve covered quite a bit of rework technique ourselves, such as last year when we looked at BGA work.
good find, thanks
I remember desoldering a ~40pin SMD ROM in my first DVD player just to make it region-free.
I used a thin copper wire to make a ribbon to weave it around each pin one by one. Then heated up the pin and pulled out the ribbon under the pin so it got separated from the circuit board.
I did the same to fix a board!!!!
Hi best method. I have been using that method since the 1960’s. Scalpel used is Swan #3 handle and #11 blade.
I just use a long enough wire to spam the length of a side plus enough extra to hold on to. I’d thread it through the entire side, behind the pins, then, starting at one end, while keeping tension on the wire, I’d hit each pin in turn. Repeat for the other side (or three). Removed cleanly enough to re-use!
Good comment. That’s been s tactic I’ve used a few times with success.
I like how he dips his solderwick in flux. That’s something I’ll give a try.
It also helps to have solder wick with good quality copper. I suggest Chemtronics 60-4-5 “soder-wick” with no-clean flux already in it. It’s wonderful. I’ll never use anything else after I found that stuff.
Man I thought I was special for coming up with this trick on my own. Mine has a variation though. I threaded long 30 awg wire behind the pins on one side of a QFP chip. I took the first end of the wire and “anchored” it nearby on the board by soldering it to something. Then took the free end and turned it 180 degrees back on itself (in front of the pins). I heat the pin with the soldering tip and pull the wire to lift each pin one-by-one.
I just flood the pins with a load of solder, heat and lift one side at a time. For the ones with all 4 sides having pins, same technique, just move around faster on all 4 sides while sticking tweezers underneath.
[Mr. Solder Fix] is superb, you really ought to take a look at the rest of his videos, I’ve been recommending his videos to people for around 6 months now.
His techniques for pretty much everything are explained and demonstrated well, especially the use of solder wick + flux and his part removal methods for large through hole parts like 10 pin headers as well as SMD.
Then there are the ripped up pad/trace repair videos… If you need to repair a PCB, these are the videos to watch.
Been doing exactly this for about 30 years now and it’s a good video.
A couple of tips…
Make sure your iron can be tinned and carry a little solder where it meets the pads. Many tiny tips won’t take a tinning so don’t be afraid to use a slightly larger chisel tip on edge. They seem to work better since they can transfer heat faster.
If the pads are tiny, just bridge a few of them with some solder, lift the leads, then use your braid.
Finally. Make sure your braid has rosin flux or you won’t get good flow. You’ll need to clean after doing the work, so don’t fry your pads or chips trying to get no clean or lead free braids to work.
The legs on eg QFP’s and SOT23’s are reasonably strong, but as soon as they go into the package, where the leadframe is, they’re not so strong. What I’ve found (and you’re not supposed to do this to your nice metcal tips) is put a bit of pressure with tweezers on the top of the leg right beside where it enters the package, to keep that section stable, and then swing the bottom of the leg up/out from the pad a little, so you’re bending the vertical section of the leg rather than concentrating all the bend right where the leg enters the package. This means prying the leg with the metcal tip, and metcal says don’t do that. But if you absolutely need to get a leg lifted without busting the package, it’s a pretty good way to do it. And yeah, lift it just a smidge and then remove the solder with solder wick. That seems to be the lowest stress on the whole system. I’m a fan of the metcal sttc-144 for fine rework and the 126 if I need to bend pins through gentle prying, because it’s a sturdier tip. STTC-190 for the very tiniest rework but these don’t last long and are quite delicate.
I find the STC-199 works for almost everything that can be soldered barring giant lugs or high temp boards.
easy If you have all the good tools to support your goal. however this is not always the case.
+1
If you’re having your own personal laboratory it sure makes a difference.
I disagree where he’s cranking the pin up and so much. Once it’s off the board and in the clear then why go further? (I don’t.)