Re: IIgs Zip accelerator SRAM speeds

[pubpc1@library.ucla.edu]

mportune@frogger.lm.com (Matt Portune) wrote,
in response to my reply:
>> need to replace it.  Someone else (Matt Portune?) posted that his
>> Zip would crash if it _did_ have the replaced part, but is stable
>> at 15MHz with the original parts.  It all depends on your particular
>
>That's right.  If I replaced the 74F gates with the specified 74HC gates,
>(either one or both) my machine won't even boot.  I'm also one of the
>people who has 15ns SRAMs across the board, with no problems.  I probably
>would have gone the 15/70 route, but the discussion about 2 different
>speeds didn't come about until I had already modified my board.

Thanks for verifying this.  Nate, if you are reading this, when are
you going to update the accelerator FAQ to reflect that the 75F gates
don't need to be (and indeed should not be) replaced in all Zips?
The FAQ's info works for _some_ Zips, but not all of them.

>Just out of curiosity, when having 15 in all 4 chips, how fast does
>your machine crash?  Is it right away, or is it over a couple hours?

With 15ns in all four sockets, it won't go faster than 9MHz before
becoming unstable.

-Scott G.