Re: Asteroids X axis problem

> > 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 13:48:57 2010