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Path: utzoo!watmath!clyde!cbosgd!ihnp4!inuxc!iubugs!iuvax!franco
From: franco@iuvax.UUCP
Newsgroups: net.micro.atari
Subject: Resistors for the ST 1MEG upgrade
Message-ID: <500027@iuvax.UUCP>
Date: Thu, 9-Jan-86 08:32:00 EST
Article-I.D.: iuvax.500027
Posted: Thu Jan  9 08:32:00 1986
Date-Received: Tue, 14-Jan-86 05:48:05 EST
Lines: 17
Nf-ID: #N:iuvax:500027:000:1059
Nf-From: iuvax!franco    Jan  9 08:32:00 1986


Regarding the 1MEG upgrade of the 520ST, the European 1040ST is simply a
piggybacked 520ST but there are no resistors in the RAS and CAS lines and
they seem to be reasonably reliable even with TOS in ROM (according to my
source).  So why do Americans need the resistors?  One theory: some, but
perhaps not all, of the upgraders have damaged their DRAMs in some way when
installing them and the resistors allow these DRAMs to function or prevent
further damage.

Further note: it has been said that the critical period for 1MEG upgrades
is between 3-5 months after the change (if anything will happen it usually
will happen then - assuming, of course, that the modification was successful
initally).  So, if you made the upgrade without the resistors and have not 
gone back to put the resistors in (perhaps because everything is fine with 
your system) and it has not been 5 months since you did the upgrade it might 
be wise to go back and do so.  Adding the resistors shouldn't hurt performance
of the ST and may prevent you from damaging your DRAMs later.