Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!lll-winken!tekbspa!oblio!charlie
From: charlie@oblio.UUCP (Charlie Richardson)
Newsgroups: comp.sys.atari.st
Subject: HELP! needed with 520STFM RAM Upgrade
Keywords: Atari 520ST RAM expansion
Message-ID: <411@oblio.UUCP>
Date: 5 Feb 89 01:24:55 GMT
Organization: Counterpoint Computers, Inc. San Jose CA 95131
Lines: 41



Please help with a problem in identifying a couple of parts needed
to upgrade a 520STFM to 1 Meg.


I have a less-than-1-year-old 520STFM which has the board layout for 4
banks of 256K/1 M  chips. This looks to be an easy upgrade (given my patience
and skill in desoldering wave-soldered component holes), but there appear
to be a few more parts (to wit, 3 resistors and 1 14-pin IC, probably a
TTL gate package) I need to complete the upgrade. Their designators are:

U 68  	(14-pin IC)

R 71
R 72	Resistors (probably same as other address line resistors)
R 73



No dealer around has schematics for this motherboard; I can't seem to get
this information. It looks to be the same motherboard as the first 1040's;
it even has a set of solder jumpers marked "256K/1MB" which implies that
1 Megabit chips could be installed to bring it up to either 2 or 4 Meg. 
When 1 Mbit DRAM prices drop to $10-12 ( maybe this summer ) this might be
an option. Has anyone performed this upgrade on the 520STFM?

Any information, comments, or pointers would be sincerely appreciated.


Thanks in advance,



================================================================================
Charlie Richardson
Acer Counterpoint, Inc.
Voice: (800) 272-8255  (408) 434-0190
UUCP: {daisy, hplabs}!oblio!charlie

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