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