Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!usc!ucsd!nprdc!malloy From: malloy@nprdc.arpa (Sean Malloy) Newsgroups: comp.sys.ibm.pc Subject: Re: Desoldering Chips Keywords: Desolder w/o destroying board? Message-ID: <3274@skinner.nprdc.arpa> Date: 14 Aug 89 19:08:48 GMT References: <1846@uceng.UC.EDU> <360@donk.UUCP> <[1427.2]comp.ibmpc;1@point.UUCP> <15014@dartvax.Dartmouth.EDU> Reply-To: malloy@nprdc.arpa (Sean Malloy) Organization: Navy Personnel R&D Center, San Diego Lines: 39 In article <15014@dartvax.Dartmouth.EDU> genemans@mac.dartmouth.edu (Jan Genemans) writes: >In article <[1427.2]comp.ibmpc;1@point.UUCP> wek@point.UUCP (Bill Kuykendall) writes: >>A simpler solution is to destroy the board with a pair of dykes and clean >>the legs off after the fact. The torch trick sounds a little radical for >>heat sensitive devices (not to mention human breathing apparatus). > >What if you have a board with an 8086 processor that is soldered on the board. >I want to remove this chip and replace it with a V30. Is there an easy way of >doing this without destroying the board with dykes or a blow torch? If you're not worried about having the 8086 around to use afterward, you can just clip the legs off the 8086, toss the DIP case, and take the legs off one by one. Alternatively, the method I used to replace the DMA chip on an old ITT Xtra was to go after each pin with a soldering iron, a solder sucker (one of the spring-loaded widgets that is sort of a hand-cocked reverse syringe), and a roll of solder wick (braided copper wire that you push onto the joint with the hot iron to wick off solder). Once all but the unavoidable minimum of solder remains on the pins, you use a small cross-shaped piece of sheet steel with two arms bent up and around the soldering iron tip (I understand you can buy these as screw-in tips for some irons, but I had the scrap) to heat the bottom of a row of pins while you press on the row with the iron and gently pull up on the same edge of the chip from the other side of the board. The solder will soften and allow you to pull the pins out of one row of holes (some of the holes may fill with solder, but the sucker or wick can take care of that. You repeat the process on the other side, and you will have removed the chip. The very next thing you do is solder a socket back in in its place, so you don't have to do this again. The whole process should take about half an hour. Sean Malloy | "The proton absorbs a photon Navy Personnel Research & Development Center | and emits two morons, a San Diego, CA 92152-6800 | lepton, a boson, and a malloy@nprdc.navy.mil | boson's mate. Why did I ever | take high-energy physics?"