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Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxn!ihnp4!ihwpt!knudsen
From: knudsen@ihwpt.UUCP (mike knudsen)
Newsgroups: net.micro.atari16
Subject: Re: UPGRADE!
Message-ID: <819@ihwpt.UUCP>
Date: Fri, 18-Apr-86 12:05:32 EST
Article-I.D.: ihwpt.819
Posted: Fri Apr 18 12:05:32 1986
Date-Received: Sun, 20-Apr-86 17:21:43 EST
References: <2585@brl-smoke.ARPA> <666@riccb.UUCP>
Distribution: net
Organization: AT&T Bell Laboratories
Lines: 24

> When I had this problem it was simply shorted address lines. With the upgrade
> ........
> If you are unlucky the shorted lines will have to be located visually because
								^^^^^^^
> you won't be able to keep the system up long enough.
> Dave Burris
> ..!ihnp4!ihopa!riccb!djb

Don't hunt for it visually at first -- that takes forever and may never
find the short.  Instead, use a modern digital VOM (Volt-Ohm-Meter),
preferably one with a "beeper" continuity check feature,
to measure between each address line and all the others.
Takes only a few minutes.  
	Once you've found the guilty pair, then go visual, or
even rip those two out and re-do them.
Don't use an old non-electronic VOM, as they may feed
high enough currents thru your chips to damage them.
Also make sure your instrument won't indicate continuity (short)
thru forward-biased solid state junctions (as in chips), thus
giving false short indications.  Test it on a diode, both directions,
to be sure.
	If you can't borrow such a VOM, Radio Shack sells them
for $40 (sale price, tho).  Worth every cent if you hack hardware.
	Best of luck, mike k