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Conference hydra::amiga_v1

Title:AMIGA NOTES
Notice:Join us in the *NEW* conference - HYDRA::AMIGA_V2
Moderator:HYDRA::MOORE
Created:Sat Apr 26 1986
Last Modified:Wed Feb 05 1992
Last Successful Update:Fri Jun 06 1997
Number of topics:5378
Total number of notes:38326

1808.0. "Help!! GURU w/accessories" by DECEAT::LANDINGHAM (Guy M., BXB1-1/F11,293-5297) Mon Oct 24 1988 14:53

Help!!!
    
I'm having a strange problem that I hope someone can help me with.  I have an
A1000 on which I have been running a 1 Meg Starboard2 for about a year.  About
three months ago I added a C Ltd SCSI 1000 host/controller board with an ST-412
and Q504 disks connected through an Adaptec 4000 controller.

For about three months, this system ran perfectly without any problems. 
Recently, I began to get the following GURU:

            00000004.00200ED2

The system boots up perfectly, runs for awhile, then crashes with the above
number.  I have found that I can *always* get the machine to crash if I run
AZComm or VT100 and log in somewhere.  The machine will always crash (again,
with the same number) after about a screenful's worth of data.

I experimented with different versions of Kickstart/Workbench (1.2, 1.3), not
loading the SCSI driver software, loading programs from floppy, etc.  All gave
the same results.  Finally, I discovered that if I leave *only* the Starboard2
or *only* the SCSI host/controller attached to the Amiga, the system will run
fine!  It is only when I have both simultaneously connected that the machine
consistently crashes.

So I have the following questions:

	- it seems obvious that my problem has to do with the expansion bus,
	  but it isn't obvious to me if it is caused by overloading the data/
	  address lines or the power supply; how do I tell?

	- what is it about using the serial port (via VT100 or AZComm) that
	  causes my crash to occur so "reliably"?

	- why did the system run perfectly for months, then begin to fail 
	  consistently

Many thanks for any help anyone can offer!
    
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1808.1P/S?RAVEN1::EVERHARTMon Oct 24 1988 15:5520
    Maybe this will help:
    	Error #4 is an illegal instruction error.  This is possibly
    caused by a failing power supply that is unable to refresh the memory
    properly.  (Someone correct me if I'm wrong)  Your power supply
    may be just powerful enough to handle both boards without anything
    extra going on, but the serial port requires power too.  That could
    be just enough to do it.  Since this worked previously, it is puzzling,
    but keep in mind that power supplies age too.  If you've ever looked
    inside a computer after a year or two of use, You'll notice that
    some of the chips have started to melt.  It is possible that the
    tolerances on the parts in you power supply have changed.  My
    suggestion is that you take You hardware to a friend who also has
    a 1000, but has not used such extra devices, and see if you can
    get it to run on his.  You may end up buying an external power supply,
    but PLEASE, don't take my word for it.  Test it first.
    
     - Chris
    
    P.S. These are only guesses.  I hope they help.
    
1808.2YES!VTHRAX::KIPG.M. Landingham 293-5297Tue Oct 25 1988 00:385
    Dug out Volume 3, Number 3 of Amazing Computing and found Perry's
    Kivolowitz's article about grounding the daughterboard PALs.  Did
    this...problem is solved!
    
    Thanks for the help.