Upgrading a Zip GS

[johnt@meaddata.com (John Townsend)]

Well, I've determined that in order to get my PCT to cohabitate with my ZIP GS,
I have to have a modification made to my ZIP board.  Even though it appears to
be a problem with the PCT, for the small fee of $100 <cough! hack!> Zip Tech
will add a cap and resistor to their board to make them compatible.  Anyway, my
real question has to do with upgrading the speed of the Zip.  It's currently at
8MHz with 64K of 70ns cache, and Zip has offered to upgrade it to 10 MHz for
the tidy sum of $250, including the mod for the PCT.  I had planned on upgrading
the speed of the thing myself to at least 12 MHz before this PCT problem came
along, and know that the cost of replacing the CPU, cache, and oscillator would
run at least $150, with no guarantee of success.  WDC sells the 65C816-E (an
engineering sample) for cold hard cash only on a "non-refundable, non-replace-
able, and non-exchangeable basis," whereas Zip will give me a 6 month warranty
on the whole board.  The problem is the speed.  Zip has given up on upgrading
their board beyond 10 MHz because, they say, it's not reliable, especially on a
ROM 01 with a lot of other cards (which I have).  However, I would at least like
to try doing 12 MHz, and if I can do so simply by replacing their 40 MHz oscil-
lator after the upgrade with a 48 MHz one, I'd be tempted to go ahead and let
them do it.  My question is whether the 65C816-10 CPU and 45ns cache that they
would put in (instead of a 65C816-E and 35ns) are likely to be sufficient for
12 MHz operation.  I asked Zip if they could put these parts in instead, and
they said that they didn't have any 65C816-E's (which makes me wonder if that's
why they had so much trouble going over 10 MHz) and that 35ns SRAMs are noisier
than 45ns ones.  I want a fast system, but reliability is important to me.  So
what would you do?

-- 
// John Townsend                 Reduce,           Reuse Engineering & Modeling
// Mead Data Central             Reuse,                ...!uunet!meaddata!johnt
// 9595 Springboro Pike          Recycle...                  johnt@meaddata.com
// Miamisburg, OH  45342            software!                    (513) 865-7250