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From: ww0n+@andrew.cmu.edu (Walter Lloyd Wimer, III)
Newsgroups: comp.sys.m6809
Subject: 512K RAM upgrades
Message-ID: <AV5EuMy00WAas-w09H@andrew.cmu.edu>
Date: Mon, 3-Aug-87 18:28:40 EDT
Article-I.D.: andrew.AV5EuMy00WAas-w09H
Posted: Mon Aug  3 18:28:40 1987
Date-Received: Tue, 4-Aug-87 06:16:09 EDT
Organization: Carnegie Mellon University
Lines: 34


A perusal of *The Rainbow* shows that everyone and his brother is
selling 512K RAM upgrades for the CoCo 3.  The prices range from
about $70 to $130.  Some include GIME chip specs, RAMdisk programs,
RAM test programs, etc.  Some advertise boards with gold-plated pins
and "fast, reliable 120 ns RAMs."  Some don't even mention the access
time for their RAMs.

I know about the flaw in the GIME timing which makes 120 ns access
RAMs the best choice for the CoCo 3.  I know you must be careful not
to push the board too far into the socket, lest the pins short out
against the tops of the capacitors.  I've also heard that a fan may
be a worthwhile investment.

When I upgraded my original CoCo to 64K I shopped around and bought
the cheapest 4164's I could find: $4.85 a peice when the going rate
was $6.95 or more.  These turned out to be high-quality 150 ns Motorola
chips which worked fine.  I was very happy.  I'm a little more wary
about the CoCo 3, though, since a satelite board and the GIME timing
problem are involved.  Does anyone have a few words of wisdom for
someone who wants to upgrade to a 512K system?  Good/bad experiences
with any of the common mail-order sources?  Are the $70 boards just as
good as the $130 boards, or do you get what you pay for?  Right now
I'm thinking of buying one in the $100 range.

Thanks for any advice.


Walt Wimer
Carnegie Mellon University

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