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Re: interesting schematic site
Bill Garber wrote:
"Michael J. Mahon" <mjmahon@aol.com> wrote in message
uNKdnT3_xLumSsvfRVn-og@comcast.com">news:uNKdnT3_xLumSsvfRVn-og@comcast.com...
: heuser.marcus@freenet.de wrote:
:
: > Thats an interesting fellow for sure. He "reverse engineered" (i.e.
: > drawing schematics of) a lot of Atari 8 bit hardware, too.
:
: I've done this for several (more obscure) cards myself--it's time-
: consuming to get it right, but sometimes it's the only way.
I've started doing a couple cards and quit, mainly because they
had PALs or GALs and I don't have the necessary equipment to
realize the logic they are set up to accomplish. To simply make
a schematic with the traces into and out of a PAL or GAL is useless.
You really need to know which are fused in and which are fused out.
Otherwise you have nothing, or Nada. :o)
Agreed--I don't even bother with such cards. I'm mostly interested
in reverse-engineering older, pre-PAL cards anyway.
: > As for the memory card: I wouldn't like the idea of "slaughtering" the
: > card and the SIMMs and the process of building his card is quiet time
: > consuming, I guess. But people in Eastern European countries have less
: > money to spend, normally, and try to invent "home solutions".
: > Especially engineers like him.
:
: But 1MB Apple memory expansions for the IIgs are a dime a dozen,
: and most users have some sitting around...
The cheapest one I've gotten was $5 individually, but have gotten a few
thrown in with a larger lot of other cards, or other items.
That's the way I got most of mine, too. But they are certainly cheaper
than a prototyping card if you can use them to build a project. And the
world is in no danger of "running out" of 1MB IIgs memory cards. ;-)
: 1MB SIMMs are also a dime a dozen (literally), so if you have the time,
: "slaughtering" some ubiquitous hardware hardly seems like a problem.
Best deal I've gotten here was $0.05 each. Not quite a dime a dozen.
Yes, I exaggerated slightly--the best deal I've found was also
five cents each--20 for a dollar. Of course, the point is that
they are neither too rare nor too valuable to sacrifice for a
useful project.
-michael
New Applesoft BASIC interface for NadaNet networking!
Home page: http://members.aol.com/MJMahon/