Re: Asteroids graphics in one corner

Dan Todd wrote:
> The board will not go into self test but plays with messed up vectors.

Seriously?

That's an important little detail. Please include all details you can think
of next time.

If you find what's causing your self-test problem, you may very well clean
up your other problems. I'd start there; it's easier to fix a hard fault
than to chase Blinky, Pinky, Inky and Clyde through a state-machine as
complex as the DVG. Pardon the pun.

You should still check your voltages first, as several people have already
suggested.

If all is well in the power supply, then start trouble shooting.

A front-end (i.e. 6502) problem could cause that symptom, but my money would
be on the DVG.

The DVG isn't typically the easiest subsystem to trouble-shoot. Having the
right tools, namely a cat box or fluke 9010 makes it a lot easier, but it
can be done with a scope and some ingenuity.

The schematics have some good circuit descriptions attached. Study both and
you'll get an idea of what you should be seeing in the circuit.

Make sure you're getting basic signs of life (i.e. vggo and halt). Since
your patient will display something in normal mode, you might be able to
find a net that's stuck. Sometimes you get lucky and these things pop out at
you.

Good Luck,
-Mark

On Tue, Nov 24, 2009 at 7:25 PM, Dan Todd <dantoddac@comcast.net> wrote:

> AD561s. On the scope the image of the game is smaller than it should be
> just
> like on the monitor. You can
> See the ship the asteroids and space ship. There are some stray vectors
> floating around and the most notable
> Thing other than the picture being small is the the push to start is at the
> bottom and the copyright is not
> Where it is supposed to be also. The board will not go into self test but
> plays with messed up vectors.
> Also when plugged into Ast Dlx cab there is no video. Just like the board
> below.
> Are the newer G05s more sensitive to some things than the older 801?
>
> Along a similar topic I just repaired one board that works fine on the
> scope
> and on a G05-801 monitor but
> When plugged into my Ast Dlx cab there is no display but plays blind. Any
> idea? Monitor in Ast Dlx is newer
> Style G05. Other Ast boards work fine in this Ast Dlx cab.
>
> Dan
>
>
> -----Original Message-----
> From: owner-vectorlist@vectorlist.org
> [mailto:owner-vectorlist@vectorlist.org] On Behalf Of Bill
> Sent: Tuesday, November 24, 2009 3:25 PM
> To: vectorlist@vectorlist.org
> Subject: RE: VECTOR: Asteroids graphics in one corner
>
> Does this board have AD561s or DAC6012s? If you look at Xout and Yout on
> an
> oscilloscope in test mode, where is the horizontal axis for the waveforms?
> They should be symmetrical around the 0V horizontal X axis.
>
> Bill
>
>
> -----Original Message-----
> From: owner-vectorlist@vectorlist.org
> [mailto:owner-vectorlist@vectorlist.org] On Behalf Of Andrew Welburn
> Sent: Tuesday, November 24, 2009 1:20 PM
> To: vectorlist@vectorlist.org
> Subject: Re: VECTOR: Asteroids graphics in one corner
>
> can you take a photo of it as it plays on a regular monitor, your first
> description is now different from this one...
>
> I'd say this was a 0v-reference problem, several suspects for it, but a
> photo would really help.
>
> Andrew Welburn
> www.andys-arcade.com
> ----- Original Message -----
> From: "Dan Todd" <dantoddac@comcast.net>
> To: <vectorlist@vectorlist.org>
> Sent: Tuesday, November 24, 2009 7:02 PM
> Subject: RE: VECTOR: Asteroids graphics in one corner
>
>
> Definitely not the monitor. I've been trying to repair a few Asteroids
> boards and got lucky with 2 so far
> Just having bad DACs, 4016s or 081 082 chips. This one I figured was a
> counter problem or something because
> The whole picture is there it is just tiny and in the lower right portion
> of
> the screen. The last board I had
> With a counter problem I had to replace 12 chips trying to figure out which
> one was bad. :(
>
> Dan
>
>
> -----Original Message-----
> From: owner-vectorlist@vectorlist.org
> [mailto:owner-vectorlist@vectorlist.org] On Behalf Of Christopher X.
> Candreva
> Sent: Tuesday, November 24, 2009 12:03 PM
> To: vectorlist@vectorlist.org
> Subject: Re: VECTOR: Asteroids graphics in one corner
>
> On Mon, 23 Nov 2009, Dan Todd wrote:
>
> > I have an asteroids board where all the graphics are showing up in the
> lower
> > right portion of the screen. The graphics are not all perfect but
> >
> > everything is recognizable. Any idea where to start looking? I?m going to
> > replace the 4016?s I?m just waiting on sockets to come in.
>
> My first thought is power supply, because it is on both axis. If you lost
> say the negative supply you might end up with only one quadrant. Offhand I
> don't remember if that would be positive or negative.
>
> ==========================================================
> Chris Candreva -- chris@westnet.com -- (914) 948-3162
> WestNet Internet Services of Westchester
> http://www.westnet.com/
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Received on Tue Nov 24 21:42:43 2009