John, What you and I do for SMT type IC's is pretty much the same.
Several years ago the wife of a close friend was in the re-work business with a home setup. What she taught me was to first line up one of the corner pins and tack solder it down. Then do the opposite corner, center the pin and tack solder it down. Do that with all four corners, taking care that the pins are properly centered before tack soldering them. Once you've got the four corners properly in places, then go and center the remaining pins; depending on the size of the chip, this might require either a microscope or very pointy eyes. Once all the pins are properly centered, flow solder over all the pins. At this point shorting all the pins together is not a problem.
Once you've flowed soldered across all of the pins you need to slurp up all of the solder with a fine pitch SolderWick. If done correctly you will wind up with all of the pins properly soldered and centered. The next step is to remove and flux using Denatured Alcohol. Once that's completed, inspect for any possible shorts or pins in the wrong place. If all looks good, cover your eyes and power it up.
I have done the above one time on my own and to my utter amazement it worked! Burt, K6OQK At 04:41 AM 4/25/2020, you wrote:
I do have a microscope (cheap Chinese unit, maybe $400 with articulated arm and the works) and it does make things much easier. But as long as you can see the work, you can do the job. It's not that hard to do small pitch parts. I usually do the best I can soldering individual pins, knowing their will be bridges, then clean up with solder wick and *lots* of no-clean flux. You can never have too much flux. I've found a 1.6 mm chisel tip is a good all around size for SMD work, though I have a 0.8 mm chisel available for when things get tight. The hardest part is getting the first couple of pins tacked down so the part is square on the pads
Burt I. Weiner Associates Broadcast Technical Services Glendale, California U.S.A. [email protected] K6OQK _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
