Whew! This one's going into the book, people!
I had an _Asteroids Deluxe_ board that worked fine, except for one thing: the big rocks tended to be VERY jumpy, particularly in the right half of the screen. All other objects behaved normally.
That clue made me wonder if it could be the DACs or not, because all other images weren't affected at all. On a hunch, I swapped the DACs to see if the problem would move. It did not.
As fate would have it, I got another batch of _Asteroids Deluxe_ boards to work on recently. To fix one of these boards, I swapped out ALL socketed chips. To my surprise, this original board now worked GREAT! Huh?
I thought, "Must have been a flaky ROM. Maybe one of the vector ROMs." Nope. Swap all the ROMs back, problem doesn't come back. Swap back the POKEY. No change.
Swap back the 6502A processor. Bingo!!!!!!!
It was the processor, the whole time!!!! It wasn't a bad socket, either, because I swapped bad 6502 with good 6502 several times to verify it.
Whew! I'm ordering a pizza. Just thought I could help add to the database of weird problems that have strange solutions.
End of line,
Matt J. McCullar
Arlington, TX
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Received on Fri Nov 3 19:40:12 2000
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