Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!wuarchive!gem.mps.ohio-state.edu!ginosko!uunet!zephyr.ens.tek.com!orca!quark!jeff From: jeff@quark.WV.TEK.COM (Jeff Beadles) Newsgroups: comp.sys.atari.st Subject: Re: Upgrading to TOS 1.4 (long) Keywords: TOS, Upgrade, Big Disclaimer Message-ID: <4734@orca.WV.TEK.COM> Date: 28 Sep 89 01:11:15 GMT References: <10035@xanth.cs.odu.edu> Sender: nobody@orca.WV.TEK.COM Reply-To: jeff@quark.WV.TEK.COM (Jeff Beadles) Distribution: usa Organization: Tektronix, Inc., Wilsonville, OR Lines: 33 In article <10035@xanth.cs.odu.edu> src@cs.odu.edu (Scott R. Chilcote) writes: > > I saved the most difficult part for last. The final step was to remove an >integrated circuit entirely from the Mega's motherboard. This chip is labeled >U12, and its only purpose is to take the ROM signals that would normally >activate six separate chips, and funnel them (through the use of a three-input >AND gate) into the two-chip ROM set. Since I needed to use all six ROM chips, >this IC had to be removed. It was difficult for me because the desoldering >braid did not remove all of the solder, and my solder-sucker couldn't vacuum >enough of it out. It took some severe wheedling to finally get this guy loose. Well, I have a MUCH easier way to remove soldered-in chips. (As long as you don't plan to re-use them.) Go out and buy a pair of diagional cutters, with a fine (small) tip. (micro-sized) When the chip is sitting in the board, cut each of the leads where they go into the silicon. Then, just pick out the "body" of the chip. Then, get a pair of small needle nose pliers (or I usually use tweezers) and pull each lead out one at a time as you touch the pad with a hot soldering iron. Then, use solder wick to clean out the holes. I have yet to destroy a printed circut run using this procedure. You might want to practice once or twice on a junk circut board. Of course, if you decide to accept this way of removing IC's, you're on your own. I won't charge you a dime, nor will I accept any responsibility if you melt-down your ST. If you've got questions about this, drop me a note. -Jeff -- Jeff Beadles Utek Engineering, Tektronix Inc. jeff@quark.WV.TEK.COM uunet!tektronix!quark.wv.tek.com!jeff