I ordered a new chip from sparkfun for only $3.95 (shipping was just as much).

Rather than waiting for the new one to come I decided in a fit of activity that the old one should be removed. With a bit of prying and desoldering it was removed. During the extraction two of the wires in the board itself got pulled up.

After a week or so the new chip arrived in the mail. I started to prep the area and fix the pulled up wires and found my old radio shack soldering iron just not up to the task. After a trip to Frys I had in hand some 60/40 solder, Rosin Flux and a new Elenco SL-540 soldering iron.

After getting the new gear it was a much easier task. I dropped a gob of flux on the pulled up wires and pushed them in to place. I dripped some solder blobs on the contacts in the corner and attached the chip. After that i just wicked away the excess using a braided wire and used a tiny bit of solder and lots of flux to get the rest of the contacts down.

Here’s the finished result: http://services.nirvanix.com/NirvanixDrive/public/email/DSC09394.JPG

http://services.nirvanix.com/NirvanixDrive/public/email/DSC09395.JPG

I was terrified of plugging it in but it turns out it works perfectly, it just looks horrible.

Thanks so much for the blog. You encouraged me to give it a try and it worked out great!

You were asking about cheap solder paste. I use this:

http://www.dealextreme.com/details.dx/sku.7952

And this is good too:

http://www.dealextreme.com/details.dx/sku.25919

Thanks for the article!

Back when I was doing SMT by hand professionally (back in the early 1980s), we were putting 144 and 168 QFPs onto circuit boards. It helps to have a soldering iron that you’ve special ground the tip to a very sharp point (This requires frequent regrinding, since the tips dissolve slowly in the solder!). Also, a 40x stereo-zoom microscope helps, too. We used very tiny solder, rather than solder paste back then.

And, yes, it was as tedious as could be! I was luck to do a couple of chips per day. I found my best time was early afternoon (e.g., when I was least shaky).

Dave

Did you have any trouble with the IC rocking as you soldered the individual feet down? I had difficulty with that when I tried your method on a board I had tinned by hand.

Know where I can get a small amount of solder paste at a reasonable price without exorbitant shipping? I’d really like to try some reflow techniques, maybe buy or build a hot air pencil, and I think solder paste is the way to go. I’m assuming I’d need a syringe, as I don’t really want to have to dab it on with a toothpick?

The technique for mounting new chips that worked best for me was to simply rely on the solder mask of the PCB for the weld. I added a small amount of paste flux to the chip legs (which also helped hold it in place on the PCB) and heated the legs briefly with a clean, small-tipped soldering iron. This resulted in a very neat soldering job.

I considered cutting the leads off and sweeping the stubs off the board with the iron. But I wasn’t 100% certain that was the bad part and I wouldn’t want to reuse it; and the leads are small enough, it would have been tricky cutting them off with diagonal cutters, and I don’t trust my aim with a Dremel.

Plus this turned out to be really the easy way. I had each side of the chip off the board in about half a minute, and I’m sure I would have spent longer than that cleaning up the chaff. So this approach did work well for me, for this chip on this board.

If you are certain the SMT part you are removing is the bad one and you are not going to use it again then you take some fine diagonal cutters, or maybe a dremel tool if you have a steady hand, and cut each lead as close as you can to the body.

Then the IC (the black part) will just come loose and you will have a bunch of little leads connected to pads. They are very easy to remove without damaging the board by grabbing the loose part with tweezers and heating up the pad. The mass of the metal is small each one comes off easily.