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From: kawakami@volcano.Berkeley.EDU (John Kawakami)
Newsgroups: comp.sys.atari.st.tech
Subject: Re: JRI SIMM board?
Message-ID: <1990Oct16.003159.1812@agate.berkeley.edu>
Date: 16 Oct 90 00:31:59 GMT
References: <1990Oct13.145427.18471@kodak.kodak.com> <1990Oct13.145829.18783@kodak.kodak.com>
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Reply-To: kawakami@volcano.Berkeley.EDU (John Kawakami)
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In article <1990Oct13.145829.18783@kodak.kodak.com> nelson@cygnus.Kodak.COM (Bruce D. Nelson) writes:
>Have any of you atari-st netters had experience with the JRI SIMM board
>for memory expansion on a 1040 (or 520). I've heard about its exisitence,
>but have seen no ads or reviews of it.

The installation was pretty simple, but I'm sure that there are people
out there who would get confused: the pictures are scrunched full of info
and not everything is flat-out stated.  If you know what an address bus is,
and know what the various electronic components look like, the installation
should not be a problem.  If not, then get someone else to do it.

The upgrade itself has little to go wrong with it: just make sure the
wires slip around the inside of the ST ok.  However, I have had problems
with HEAT.  It's pretty crowded in a 520ST and I noticed that the chips
get HOT.  The JRI board covers part of the 68000 and other chips, and
also brings in some RAM chips and makes the whole shebang heat up like
a toaster.  I had problems with the RAM flaking out on me: the screen
would fill up with garbage on from one bank of SIMMs overheating.*
I "cured" this by removing the RF shielding and raising the board off
the motherboard (with a cardboard standoff).

This seems to be a not uncommon problem from the mail I have received.
Another cure are to get cooler RAM (I have "Magic SIMMs" Maybe the answer
is to get "better" name brand SIMMs with Micron or Japanese chips) another
is to get a fan, another is to get a STe.

* SIMMs come 8 bits at a time, so you need two SIMMs for the ST: a 16
bit word size machine.  The SIMMs sockets are angled so the SIMMs "lie"
on top of each other like bacon.  I figured it was the bank caught under
the other SIMM that got hot and flaked.  When I swapped SIMMs, the garbage
showed up on the same half of the 16 bit word.

John Kawakami                  kawakami@ocf.berkeley.edu
                               ucbvax!ocf.berkeley.edu!kawakami
Amateur crank!                 My Atari Macks!