Re: [stella] Space Treat new version

Subject: Re: [stella] Space Treat new version
From: "Eckhard Stolberg" <Eckhard_Stolberg@xxxxxx>
Date: Thu, 26 Dec 2002 21:42:04 +0100
> Ouch, so the issues must be specific to PAL 7800s only... this gets things
> even more complicated :(

Looking at a trace log of your game I would guess that your
sychonizing problem comes from the fact that you are setting
a timer and resetting the collisions during the three lines of
VSYNC. I had problems with that on my old PAL TV with some
demos from this list, that did that too, some years ago.

Thinking about it now, I was using a 2600 Jr. console, that
has one of the TIAs that have the positioning problem in
Kool Aid Man, back then. All PAL 7800s, that I have seen,
have this version of the TIA chip too. If the synchonizing
problem only happens on these TIA chips, it would explain,
why Space Treat would have problems on your 7800 but works
fine for almost everyone else. This would also explain,
why no-one but me was able to confirm this problem in the
last couple of years. ;-)

If you have several 2600 Jrs. available, you could try out
if one of them has a positioning problem with the score in
Kool Aid Man. Then you could see, if Space Treat wouldn't sync
with your TV as well on this console.

To fix the problem, you could try not to do anything during
the three lines of VSYNC. Just do three WSYNC in a row. Maybe
then your game would work on your 7800 too.

Ciao, Eckhard Stolberg

Archives (includes files) at
Unsub & more at

Current Thread