DON'T TIN THE PADS! You'll end up with major problems getting the QFP to sit down, leading to unsoldered pins! If you have a microscope, use it!!! Gently place the QFP on the board. They sell special vacumm wands that work good, but gently setting down then sliding it into position works ok (put these chips on first). Get the part into the approximate position, then finely align one corner. Tack one pin down. Align the other corner. You can twist the part one or two pads without damage, but more is bad. Unsolder the first pad if it is too far out of alignment. Use solder wick to clean all traces of solder off the pad and start over. Once you get two opposite corners tacked, make sure your pin 1 is correct, and all the remaining pins are over the correct pads. It's pretty easy to shift the whole package by a little bit, especially if you don't have a microscope. Apply a water soluble liquid flux to one entire side of the chip. Really goop it on. It doesn't hurt, and you can wash off the excess. I've tried soldering one pin at a time, and never had any luck with it. The way I was shown was to use a pretty fine tip with a 45 degree angle about 1/2 inch from the tip. If you lay the 1/2 inch part of the tip in the crotch formed by the pin legs, you heat a number of pins, with the pin at the tip getting the most heat. Put a smallish blob of solder on the first 3 pins furthest away from you (yes, solder bridge), and using the tip drag the blob towards you and onto more pins. If you have the heat right, the surface tension of the solder will leave perfectly soldered joints on the pins you are moving off of, and the blob will solder the pins you are starting to cover. You'll have to back up occasionally to pick the blob back up. After practice, I can solder a 208 pin QFP in about 2 minutes start to finish. If you screw up, DONT try to remove the part. You'll ruin the board, and the part too. If you must remove the part, use a dremel tool to cut the pins loose from the package, very carefully so you don't rip the traces off the board. Then desolder each pin individually (pretty easy). You can also heat one pin at a time, then bend it out of the way with tweezers. You'll ruin the part, but it's better than ruining the board. You can save the part by heating the underside of the board with a plumbing torch, then tapping the edge gently to dislodge the parts when the solder melts. Good luck! Clint PS If I was you, I'd try and find someone that does electronic assembly for a living, and give them twenty bucks to solder the parts on. For twenty bucks, they'd probably be willing to build the entire board for you, but you might enjoy that part of the work... On Thu, 24 Jan 2002, Peter C. Wallace wrote: