SMD work

[reabbott]

Has anyone ever successfully hand soldered any surface mount components ? Ive reading up about this next step in my soldering evolution and it looks surprisingly straightforward. Does anyone here have any experiences or stories, failure or success ?

Russ.

[smason]

Re: SMD work

It looks easy. But when your eyesight starts to go. and you're sleep-deprived and caffeine-fueled it's not so good.

I wasn't paying attention the other night and removed a small surface mount diode instead of a fuse. Took 20 minutes to find it, glasses and a 20x magnifier to fing which end was the cathode, and another 15 minutes to put it back on the board.

Sucks to get old....

[Mad_Professor]

Re: SMD work

https://www.badcaps.net/forum/showthread.php?t=23477

That and some zener/diodes, smps chip replacement too.

All I can say, smaller the chisel tip is, the better, also get some headmount magnifying set, prefer one with adjustable lighting position. Also thinner solder helps too.

[randtek]

Re: SMD work

I have been replacing SMD components for many (30+) years. I was working with SMD devices in the military long before they appeared in consumer equipment. You want to use very fine solder. If you don't have much need for solder this fine, I have had reasonable success using standard diameter solder, but I take a piece and VERY SLOWLY and gently stretch it until it breaks. There will be about 1/4" of thinner, stretched solder where it breaks. That is plenty for most small SMDs. Not really practical for the IC's with many pins.

After removing the old device, clean ALL old solder from the pads using solder braid. You want the pads to be smooth, with no lumps of solder. Add a small amount of solder to one of the pads, so it has a small bump of new solder. It is unnecessary to add solder to the new device prior to soldering, they are pre-tinned. Set the SMD component on the circuit board, in close proximity to it's final position. Using a pair of very fine needle nose pliers, move the component onto the pre-soldered pad, while holding the soldering iron on the pad to melt the solder. Hold it in place for a few seconds after removing the iron, until the solder solidifies. It won't take long, as the pads, solder and component are all pretty small. Once you have one pad holding the component in place, put down the needle nose pliers, and add a tiny bit of solder to each connection, by placing the soldering iron tip at the junction of the component and solder pad. Just touch the solder to the junction long enough to melt a tiny bit onto the connection, then remove both the solder and the iron. The solder should melt pretty much instantly, as soon as you touch it to the junction.

[999999999]

Re: SMD work

Go to a mom-n-pop computer shop, or Goodwill, and grab some free or nearly so old electronic items with SMD components and practice. Computer motherboards and hard drives come to mind as two likely candidates, you may even have some lying around to practice on.

[spleenharvester]

Re: SMD work

Recently started, and by recently I mean I've done it a couple of times. It's easy enough if you have a low-wattage iron (mine is 12W) and you learn to drag solder.

Get a decent pair of tweezers, some flux etc. Try it on some dead motherboards (I always keep dead hardware round for practicing on).

If you've not soldered before you may not be so adept. But a few hours replacing my 40W iron with a 12W iron I'd already managed to solder one of these (though bear in mind I had to use an airgun once the pads were tinned): http://img522.*************/img522/7900/pict0101eo.jpg