Asteroids Deluxe RAM Problems (was: 2114 RAM speed)

Thanks to David Fish for sending me the data sheet on
the SCM21C14-4 RAM. Unfortunately, that didn't
provide the smoking gun I was hoping for. Maybe
someone here could provide a little more insight into
the problem I was having.

Problem: Asteroids Deluxe board. Reporting a bad
program RAM in self test. When tested with a Fluke
9100, it tested fine. Swapped out said RAM and the
board now works. The only conclusion that I could
draw from this was that the RAM was too slow for this
application. Unfortunately, from the data sheet that
David sent, it shows that the RAM was a -200 ns part,
which should be more than sufficient for this
application.

Any thoughts on why this particular RAM wouldn't work
on an Asteroids Deluxe board? The only thing that
caught my attention on the data sheet was a statement
that says: "For NMOS 2114 replacement applications,
note the timing differences for /CE; where /CE access
is required to be faster than address access, use the
SCM2114AL." However, I don't think this would apply
to the Ast Dlx board since the address lines are
already stable before the /CE is triggered (by the
address lines). I'm stummped.

Thanks,
-Chris

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Received on Sat Aug 24 10:47:47 2002