Dragon's Lair Fans - Arcade Lifestyle
General Chat => Technical Area => Topic started by: nilfisk on September 14, 2015, 02:33:49 PM
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Dear All,
Some of you may remember that I've been struggling with fixing one (in fact, two ;)) of my Galaxian PCBs over the last few months. I've now got one of them running almost perfectly, with one strange issue remaining:
Whenever a group of three ships attacks, the right Guardian is invisible while diving. However, it re-appears in any of these cases:
- the group misses my ship and returns to the top (see video)
- the left, visible Guardian is shot - then, even while still diving, the right Guardian suddenly becomes visible.
It's just invisible, other than that, it behaves normally, in that it fires bullets, and also can be shot, if you guess it's position.
This video should serve as a better explanation than my summary above, I suppose ;)
https://www.youtube.com/watch?v=O7WtKVJ-7GU
The sprite ram is good, as are the graphic eproms etc.
As always, any hints are highly appreciated!
Cheers,
Martin
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Can't see the video...it's private....
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You're right, thanks for the hint. Should be public now.
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That's a difficult problem to diagnose because the sprite hardware is quite complicated on this game. There's a good description of how sprites are generated in the MAME driver:
\src\mame\video\galaxian.c
https://github.com/mamedev/mame/blob/master/src/mame/video/galaxian.c (https://github.com/mamedev/mame/blob/master/src/mame/video/galaxian.c)
Paul.
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Thanks, Paul!
It seems i found the fault. While doing some online research, I stumbled upon this post on KLOV, describing my exact problem:
http://forums.arcade-museum.com/archive/index.php/t-187726.html
And indeed, I am using 2701 RAMs, as pullups are present on my PCB (and, coincidentally, it also is a bootleg / Atari license, not a Namco/Miday pcb). So I swapped out 1P-1S with 2700s, and removed the resistors - now the third enemy is back :)
Sprite RAM Area:
(http://www.kersch.at/galaxian1.jpg)
Atari Factory Stamp:
(http://www.kersch.at/galaxian2.jpg)
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Huuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuhhhhhhhhhhhh ?!?!?!?!?
Galaxian Atari licensed ? Atari Europe ?? "Now brakes my wooden shoe !` (as we would say in Dutch ;) )
Need pic of full PCB please...please :D
I was about to point you to exactly this info here:
http://www.arcades.plus.com/galaxianfix.htm
and describes the same issue :D
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There you go ;)
(http://www.kersch.at/galaxian3.jpg)
Except for being setup for DC right from the start, and missing the beforementioned buffer IC, it's an exact copy of the Namco/Miday boards.
I bought this on Ebay a few weeks ago, sold as "working". Upon arrival, it turned out it was missing RAMs (thus the 2701s), and someone has scrapped the sound section for spare parts ::)
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Interesting. The GGI bootleg I was working on doesn't have the latch either and someone has cut out the pullups on that too...
Paul.
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Mmmmm, nog a very clear picture but it does seem to have the typical Atari light green color...
Atari Europe was used by The French factory and this board came from France.....so.....could there have been a Galaxian licensed from Atari Europe/France ?
Any other stamps/ markings/numbers ?
Very Interesting.....
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There is a general theory that Atari Europe (France) locally "licensed" some games from other manufacturers. The Galaxian platform had a lot of games on it, so if yours is converted we may not be able to determine what game it might have been. Interesting find!
Paul.
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There is a general theory that Atari Europe (France) locally "licensed" some games from other manufacturers. The Galaxian platform had a lot of games on it, so if yours is converted we may not be able to determine what game it might have been. Interesting find!
Paul.
It wasn't converted. I dumped the original Roms before doing the single rom hack, and they contained a variety of the original Galaxian (without Namco or Midway copyright, but other than that, true to the original).
Martin
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Full on bootleg then :)
A chatted with P-Man a little and he heard a rumour that Atari France did board repairs and stamped all the boards they repaired so that's another possibility.
Paul.
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Hah, I already thought about asking Andy as he knows a lot about those things...kind of a bummer if that is what it is though....
I could post the pics on the Atari Museum Facebook page, there are some guys there who wrote the recent Atari book Business is fun and probably have the deepest Atari knowledge on earth ;) (And there are also some ex-employees there.)
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Guess what......my Asteroids board from him also has Atari Europe and "Baums" stamps (thought the town name where production was called Baumes though ?)