Re: Asteroids X axis problem

Does your machine have the original power brick? If it was swapped in from
another game, the plus/minus supply voltage might be too low. Also check
the transformer taps used to set the output voltage. I have a feeling that
the AC output voltage is running too low. The long axis is showing the
limiting or walling effect because the deflection transistors are saturating
due to insufficient DC power supply voltage.

Be aware that a GO5-801 monitor required plus/minus 25-28 VAC power supply
whereas the GO5-802 required 35-37 VAC. If your monitor is an 802 and your
brick is set for an 801, that's your problem.

William Boucher

----- Original Message -----
From: <arcaderelics@irongiant.org.uk>
To: <vectorlist@vectorlist.org>
Sent: Thursday, March 11, 2010 5:55 PM
Subject: Re: VECTOR: Asteroids X axis problem

>
>>Does the test pattern similarly degernate into a line at the edges unelss
>>the size is reduced?
>
> Yeah, it kind of mashes up the diagonals as they hit the far left and
> right edges.
>
>>Are your +15V & -15V good?
>
> Yup, no problems there.
>
>
> Thanks,
> Phil
>
>
>
>>--- 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 18:39:08 2010