Archived from groups: rec.games.video.arcade.collecting,rec.games.video.arcade.marketplace,rec.games.pinball (
More info?)
Zinfer wrote:
> Where do you get the Eproms at again?
Sometimes on eBay, sometimes directly via contacts.
It helps to be able to buy in bulk.
When I started a few year back, I was only buying 10-20 Eproms at once.
Now it's 100-200 at a time. Obviously price per units drops with qty.
> I imagine you keep quite a stock on hand.
> Thing is, I'm sure that alot of different games use
> alot of different Roms. Do you know of any that are really widely
> used that are good to keep on hand in particular?
I have about 20 different Eproms on hand,
plus about 10-15 other chip types ( Proms, CPU, Memory, etc...).
In total I now have about 3000 Eproms/Proms/CPUs on hand.
So the really custom stuff, I can usually find something
at Jameco, Mouser or DigiKey, although that gets expensive...
The easy thing about eproms it that "most" games from the same era use
the same type of chips. Pre-80's game used 2716, early 80's (Pac for
instance) used 2532 or 2732. The newer the game, the bigger the Eprom
size. Newer [90's] games often use 16M (27c160) chips.
Most DMD pinballs use 4M (27c040) or even 8M chips (27c080).
So depending on which type of game you collect,
you can limit yourself to those types of Eproms.
> It'd sure be nice if there were a diagram that had like:
> Midway=1892304 roms
> Atari= 1355900 roms
> Taito=38599595 roms
Actually, early games are easier because there really weren't that many
types of chip available. The real trick if finding the "correct" Rom
image to burn. Many games have bootlegs, copies, or upgrades, not to
mention the numerous hacks that have evolved along the way.
I'd say the 80% of my time is spent doing research for the right image,
and the actual burning is pretty quick.
Later games are a little more difficults because of the proliferation
of Eproms types ( 8 bit, 16 bits, masked, etc... ).
There is no "bible" of which Eprom to use of which game,
(...that I know of...) but that would certainly be something
worthy of starting. (...I'll add that to my pile of projects !) ;-)
> One could probably use the existing rom unless it's bad altogether to
> reprogram it, but I wouldn't know if that's a bad or good idea to wipe
> out a Rom which may be good anyhow.
I always make backups of any chip I'm trying to upgrade/fix
before erasing it.
Erasing is usually pretty easy and safe.
(...but you'll need a special UV light to erase the Eproms )
You'll know pretty quickly if an Eprom is bad
because it will not be able to fully erase
or it will not program correctly.
I usually burn a chip on one programmer and then
re-read it on another burner to make sure the Checksums match.
(..I do this in the almost impossible case where
a burner programs badly and then reads incorrectly to
give a "correct" checksum )
Only very, very rarely will an Eprom erase and re-proram properly
only to "lose" it's programming later on.
> Be nice to learn more about it but I guess you have to have some roms
> on hand to practice with first.
>
That helps ... ;-)
Cheers,
Steph
www.HobbyRoms.com
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