Re: Copying Asteroids ROM 035127

> The three main program ROMs (two are EPROMs, one a ROM) copy just fine and
> the copies work okay. However, the final ROM (035127 at location N/P3)
> copies okay but the copy won't work. Or rather, with the copy plugged into
> the board the game just goes into a loop with a constant beeping, flashing
> of the player one/two LEDs and flashing diagonal line on the screen. Pop
> the original ROM back in and all is well again.

Yeah, those are the vector ROMs. They're supposed to be 2716s or
equivalents. Sounds like the images you've programmed into them that
aren't right for that game ROMset or else the parts are bad/too slow.

> I've tried copying this twice - both times the copies verify and checksum
> okay against the original.

Don't bother with checksums. There are zillions of ways to compute 'em and
it's just flatly confusing. Just compare them with the original images you
have on disk.

It's funny. I've seen people send ROM images through ZIP files (which has
a MUCH more stringent error checking mechanism) yet still insist on
checking the checksums.

> Am I also correct in stating that this is the Vector ROM?

Yes.

> Where am I going wrong? Maybe my (rather old) programmer isn't handling it
> correctly, or do I have to read it in as a different type?

Sounds like your 2716 might be too slow. They need to be 200ns or better
(smaller).

-->Neil

-------------------------------------------------------------------------------
Neil Bradley Whoever said "Money can't buy happiness" didn't have
Synthcom Systems, Inc. a lot of money.
ICQ #29402898

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Received on Sat Feb 2 15:26:40 2002