Re: Asteroids X axis problem

Does the test pattern similarly degernate into a line at the edges unelss the size is reduced?

Are your +15V & -15V good?

df

--- On Thu, 3/11/10, arcaderelics@irongiant.org.uk <arcaderelics@irongiant.org.uk> wrote:

> From: arcaderelics@irongiant.org.uk <arcaderelics@irongiant.org.uk>
> Subject: Re: VECTOR: Asteroids X axis problem
> To: vectorlist@vectorlist.org
> Date: Thursday, March 11, 2010, 1:53 PM
>
> > > I can't unfortunately see any faults when I
> 'scope out the signals.
> > When you "scope out" which signals? If the output
> (X&Y) looks good, then you're looking at a monitor
> problem.
> >
> > Either way, it sounds like a problem in one of the
> analog sections (monitor or board), as in a signal
> clipping.
>
> The 4016 has been replaced as it was faulty (total screen
> collapse in the X axis) so perhaps the TL081 or TL082 ?
>
> Perhaps even the AD561 ?
>
> > If you make the picture smaller, does the "vertical
> line" unfold in an object?
>
> Sorry, Forgot to mention - the problem goes away if the
> picture is reduced to 'small to moderate' size in the X axis
> - if it's between moderate to large then the fault occurs.
>
> > Do you have a picture?
>
> Afraid not, not much to see really though, just a vertical
> line the height of the object as it passes through the edge
> of the screen (the object is still drawn okay though).
>
>
> Thanks,
> Phil
>
>
>
> >
> > -Mark
> >
> >
> >
> > Just been fixing up my first Asteroids board for ages
> - multiple problems, all now fixed ......... except for
> one.
> >
> > Whenever an object gets to the far left or right edges
> of the display it's still drawn okay BUT as the object
> passes through the edge it makes a vertical line at that
> edge where the object is passing through - the line is same
> 'height' as the object too.
> >
> > Now I've seen something similar before which was
> caused by a problem with the UNMDACX12 signal, but in this
> case that's not the problem as changing the relevant chips
> (7404 at H10 and LS191 at C9) doesn't fix the fault.
> >
> > This is an early Rev 2 board.
> >
> > Could of course be the AD561 DAC, or the TL081 or
> TL082 in the X axis output circuit, but is there anything
> else that I've missed before I go swapping out multiple
> chips? I can't unfortunately see any faults when I 'scope
> out the signals.
> >
> >
> > Thanks,
> > Phil
> >

      
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Received on Thu Mar 11 14:02:58 2010