Originally posted by: CallMeJoe
For a job like this, call for a
technician, not an engineer. You want someone who can actually do the work, not design the circuit.
First, get a good
Antex 15 watt iron, and a needle point (the 1/64" gold tip on that page is ideal). A good
flux pen and some
fine gauge solder are next. Hot air is the preferred method for removal, but if you don't have the equipment, you will need some precision tip cutting pliers (sorry, no handy link) to cut the individual leads, then remove them one-by-one with the iron. If you try to desolder all the leads with an iron and then lift the chip off, you will surely trash the board. Clean the solder pads on the board with some solder wick, then lightly tin one pad on each corner, place the IC on the board, apply liquid flux to the pads and briefly touch each lead to melt the solder. Spread flux across the remaining leads and solder the leads one by one, being careful to limit your dwell time on each lead to not more than one second, and allowing a brief cooling period before proceeding to the next pad. Work patiently, and examine each pad carefully with a magnifier when you are done. If you find and solder bridges, clean them off with the iron and some solder wick. As stated previously, clearing bridges with an exacto knife is likely to do more damage than good.
If all this sounds tedious and difficult, it is. I work in an avionics shop with three other techs, each with more than 30 years electronics experience, and they all leave jobs like this to me (factory trained and certified by a major manufacturer in SMD repair)