Soldering surface mount components sucks!

[bobotech]

I do a large amount of laptop repairs.  I can strip down pretty much any laptop to its motherboard in under 1/2 hour and put it back together in 45 minutes without so much as a single left over screw. 

With that said, a lot of troubleshooting is done with the motherboard sitting on my table powered up after being removed from the case.   well I was doing that on friday like normal (had a hard freezing machine). 

Well I powered up a motherboard to test something and then I promptly forgot that I had power to it and proceeded to plug in the monitor video harness cable onto the motherboard but slipped a tiny bit.

Zzzzaaapp.  Heard the noise and smelt the magic genie smoke being let out of the component.  The board still powered up but no longer had internal video but external video still worked fine.  Used my magnifying glass and found a burned up inductor next to the video input.  The thing was TINY.  No bigger than a SMD resistor.

I then dug though my pile of crap and found an old laptop motherboard and looked for a similar inductor.  Inductors seem to have no markings and the burned up one was well, burned up anyway.  I found an inductor on the motherboard, well it had 6 of them.  I tried to desolder 4 of them and proceeded to ruin each one.  On the 5th one, I almost saved it but broke it at the last minute.  I then realized that part of the problem is that SMD components are glued to the board then wave soldered so not only was I fighting the solder, but I also had to break the glue bond.  Very carefully I managed to desolder and pry up the last inductor (they are not common at all unlike resistors or capacitors).  I then had to solder it on to the motherboard.  Boy that was annoying.  Had to use my magnafying glass again to see what i was doing.  I finally managed to get the chip soldered in place and the internal video worked again!

I was so relieved but man, I hope not to have to do that again!

[lilshawn]

bravo! 

you probably could have just jumped the inductor with solder and probably been okay. you might have had a tiny bit of noise in the video... but it's good you got it working...

inductors tend to filter out really high frequency noise from a signal without the loss of voltage like with resistors (which they used to(and even sometimes still use))

[boykster]

yes, SMD soldering is tough! 

[jennifer]

       You made that story so exciting.... completly horrifing, OMG, I can"t watch, but then the day is saved.
Maybe you should order a couple spares if you do a lot of that kind of thing.

[lilshawn]

I have to replace the LM311s on the buckhunter gun optical sensors all the time. They are surface mounted 8 pin dips a little smaller than a pencil eraser. Thankfully the optical boards are either too mass produced, or not mass produced enough for them to glue the components down before soldering.  removal is as simple as globing on some solder onto either side and heating up one side good and hot... Once I heat up the solder on
the other side enough for it to flow, it slides right off.

Once you do it a few times, it's pretty easy. You get used to how small things are and how much coffee effects your ability to do it.

A magnifying glass really helps, especially when you have several components close together. You can see if there is a solder bridging between the legs or adjoining components.

[RandyT]

Glue costs more and takes more time.  Boards which have the SMD components glued and soldered are not very common, which is apparent if you have seen some of these new high-speed part placement machines in action.  In most cases, it's a simple matter of using hot air and tweezers.  Heat it up and pluck it off.  Putting it back is nearly just as easy.  Clean the pad, apply a dab of solder paste, stick the part in the goop, and apply hot air.  Done

[Howard_Casto]

Glue costs more and takes more time.  Boards which have the SMD components glued and soldered are not very common, which is apparent if you have seen some of these new high-speed part placement machines in action.  In most cases, it's a simple matter of using hot air and tweezers.  Heat it up and pluck it off.  Putting it back is nearly just as easy.  Clean the pad, apply a dab of solder paste, stick the part in the goop, and apply hot air.  Done

Yeah... not to be a know-it-all but I was thinking myself that the reason you wre having such a hard time soldering smd components is because you aren't supposed to solder them.  Or at least not in the tradtional sense.