512K -> 1.5M piggy-back memory upgrade

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Article #1634

#1634

From: stephen.m.marcus
Date: Wed, 19 Jul 1989 18:01

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I have what was an original Mac 128, upgraded to 512KE.
I have further upgraded to 1M by piggy-backing a layer of
DRAMs on the mother board, plus adding a couple of TTL 
chips for address decoding.

I'd like to add a further layer of DRAMs to extend memory
to 1.5MB - the maximum that's physically possible given the
physical space and the phut left in the power supply.

Does anyone have details they can send me on the additional 
memory decoding necessary to do this?

Please e-mail directly to me.  I will summarize and post to 
the net.

Thanks

Stephen Marcus
att!iexist!marcus
marcus@iexist.att.com
(312) 713 5256 / (312) 355 5311 (home)

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Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!cs.utexas.edu!usc!apple!rutgers!bellcore!att!cbnewsc!marcus
From: marcus@cbnewsc.ATT.COM (stephen.m.marcus)
Newsgroups: comp.sys.mac
Subject: 512K -> 1.5M piggy-back memory upgrade
Keywords: memory upgrade
Message-ID: <1860@cbnewsc.ATT.COM>
Date: 19 Jul 89 18:01:30 GMT
Distribution: usa
Organization: AT&T Bell Laboratories
Lines: 21