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From: jacc@tekigm2.TEK.COM (Jonathan A. Colby)
Newsgroups: comp.sys.amiga
Subject: Re: Amiga Disk & HAM problems
Message-ID: <1731@tekigm2.TEK.COM>
Date: Sat, 9-May-87 18:26:18 EDT
Article-I.D.: tekigm2.1731
Posted: Sat May  9 18:26:18 1987
Date-Received: Sun, 10-May-87 08:57:55 EDT
References: <867@isrnix.UUCP>
Reply-To: jacc@tekigm2.TEK.COM (Jac Colby)
Organization: Tektronix, Inc., Beaverton, OR.
Lines: 45
Keywords: flicker io errors

News/NSA line eater sharefood: terrorist cryptography DES drugs cipher LSD

In article <867@isrnix.UUCP> you write:
>My Amiga tends to trash disks fairly regularly.  Enough to be very
>frustrating...

>Now, my Amiga also has another problem.  When I display the 'brick.img'
>ray-traced DBW picture a section of a line (about 1 inch long) half way down
>the screen will flicker from what it should be to a solid line of
>another color....

>I recently added a TechniSoft 2m expansion to my Amiga and upgraded
>the PAL's.  The problem has not changed in any way since I added/upgraded
>them.

>Is it possible that the two problems are related?  Do Floppy I/O and
>video generation ever hang out together on any of the custom
>chips?

I recently added the 1 meg Aminetics "Squeeze-Ram" board and
experienced a set of symptoms that my offer a clue to your
problem.  After the 3-4 hour assembly and installation, the 
Amiga booted right up, but a number of programs had problems.
Textcraft didn't work: "blotchers appeared where the sprite
cursor should have.  Quicknibble exhibited "bit-rot" (a few
pixels here and there were the wrong color), and hung as soon
as you tried to copy a disk.  And emacs STARTED CRASHING DISKS!

I removed the Squeeze-Ram and all worked well.  Aminetics
provided a fix, and so far, all is well.  Significantly, the fix
was to add .047uf caps to the memory address decode chips to
clean up the signals.  My experience strongly suggests that
interference with Chip ram memory timing can crash disks.

Have you attached anything else to your Amiga that might affect
Chip ram timing?  Check out the fixes for the C-Ltd SCSI adapter; 
I seem to recall that some of the suggestions delt with cleaning
up timing and signals.

Jac Colby	- they disclaim me around here, too.
Personal Engineering Products Project, Tektronix Inc.
UUCP: {ucbvax,decvax,pur-ee,cbosg,ihnss}!tektronix!tekigm2!jacc
-or-  jacc@tekigm2.TEK.COM
      5529 SW Patton Rd, Portland, OR 97221       (503) 292-1609
-or-  MS 02-386, PO Box 500, Beaverton, OR, 97077 (503) 627-4534