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From: bammi@cwruecmp.UUCP (Jwahar R. Bammi)
Newsgroups: net.micro.atari16
Subject: Re: UPGRADE!
Message-ID: <1461@cwruecmp.UUCP>
Date: Mon, 14-Apr-86 21:16:32 EST
Article-I.D.: cwruecmp.1461
Posted: Mon Apr 14 21:16:32 1986
Date-Received: Wed, 16-Apr-86 04:51:09 EST
References: <2585@brl-smoke.ARPA>
Distribution: net
Organization: CWRU Dept. Computer Eng., Cleveland, OH
Lines: 37

> foo!
> Well I did it. I attempted the fatal up grade. The good news is that I
> did not fry my ST. She boots-up all right along with the 5 or six
> accessories on the desk top [fonts,ramdisk,etc...]. The ramdisk says
> ~690+K byte available! Looks  good right!?
> 
> However a little after after boot-up,vertical lines appear up and down
> across the whole screen!!! Sometimes the lines shift color as I move the
> mouse. I can still run programs, copy files to and from the RAM disk,
> but invariably, after a short time it crashes, lines and all. My
> thinking is that one of the RAM chips is flakey. WHy?
> 
> 	A. the vertical lines appear on every 8th pixel
> 					      ---------
> 	B. When pressing memory to its limit by coping whole disks into
> 	   the RAM disk, I can see the patterns of these vertical lines
> 	   change in exact sequence with the "clicks" of the floppy disk.
> 
> Questions: 1. Any suggestions on what else it might be? 
> 	   2. How does one test for a bad RAM chip?
> 
> 		All comments will be MOST welcome. Thanks - Geoff
> 				     ****

*** REPLACE THIS LINE WITH YOUR MESSAGE ***
It looks like that you certainly have a bad bit. Since the screen
memory is placed in the uppermost 32k of memory, you can see it on the
screen. I would suggest using sed to deposity end retrive bytes from
addresses in the upper 512k range to determine which bit is bad, and
then replace the chip coresponding to that bit.

-- 
					Jwahar R. Bammi
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