[comp.sys.amiga.hardware] A3000 Video Problem

groleau@thunder.mcrcim.mcgill.edu (Francois Groleau) (02/18/91)

I got my A3000/25 a month ago and I have a very annoying problem.

The problem is with the video ouput and is intermittent.  Sometimes, the active
window on the workbench will get filled with garbage in an orderly fashion.  I
get lines about 20-pixel wide going down a bit from left to right (as if I was
seeing the retrace line on an old monochrome PC-monitor but here the line is
not a single-pixel wide).  I had this problem while using the Shell, VLT, and
ED.

I said the problem is intermittent but last night, I was able to get it to
show up consistently.  I was displaying an iff picture with a height larger
than my overscan setup whereas the width was smaller.  Again I could see these
sorts of wide vertical retrace lines and I noticed that they seemed to behave
like sprites (i.e. the lines would sometime jump and the picture underneath was
not corrupted).

I have a 14 MB system so I am using the full 2 megs of chip ram.  I have the
A1950 Multisync monitor.

PLEASE HELP ME!  If anyone had a similar problem or if you, people from 
Commodore, know what is going on, I would be really pleased to get an answer.

I forgot to mention that strangely enough, the capacitor near the '882 and
close to the front of the computer is literaly cut in two.  Is this a hardware
modification that I should not care about (although I doubt it...)

Francois Groleau |  Going on means going far...  |     // Only Amiga!
McRCIM           |  ...going far means returning |    //
McGill University|                               |\\ //   Proud owner of an
Montreal, Canada |<groleau@moe.mcrcim.mcgill.edu>| \X/    Amiga 3000!

groleau@thunder.mcrcim.mcgill.edu (Francois Groleau) (02/18/91)

In my last posting, I am talking about vertical retrace and I only confused
people.  After verification, I believe I cannot associate what I am getting
with a vertical retrace pattern.  To clear up things, here is what I see
on the screen:

	+----------------------------------+
	|				   |
	|=========== <------------------------- 20-pixel wide sprite-like
	|           ==============         |    noisy line that appears
	|                         =========|    intermittently in Wbench
	|===========                       |    windows but consistently
	|           ==============         |    when displaying picture
	|                         =========|    that is 280x550 (higher
	.                                  |    than overscan height).
        .                                  .
	.      and so on...                .
        .                                  .
        |                                  |
        +----------------------------------+

Still waiting for help...

Francois Groleau |  Going on means going far...  |     // Only Amiga!
McRCIM           |  ...going far means returning |    //
McGill University|                               |\\ //   Proud owner of an
Montreal, Canada |<groleau@moe.mcrcim.mcgill.edu>| \X/    Amiga 3000!