Xref: utzoo comp.sys.att:4955 unix-pc.general:1884
Path: utzoo!utgpu!watmath!uunet!xanth!ames!vsi1!daver!mfgfoc!mike
From: mike@mfgfoc.uucp (Mike Thompson)
Newsgroups: comp.sys.att,unix-pc.general
Subject: Re: Call for Help:  3B1 1MB to 2MB upgrade
Summary: has anyone tried to piggyback ram chips before?
Keywords: Any hardware gurus out there?
Message-ID: <520@mfgfoc.uucp>
Date: 16 Dec 88 22:50:41 GMT
References: <803@ttrde.UUCP> <2653@cbnews.ATT.COM>
Organization: Focus Semiconductor Sys, Sunnyvale
Lines: 28

From article <2653@cbnews.ATT.COM>, by mvadh@cbnews.ATT.COM (andrew.d.hay):
> 
> btw, it looks (from the schematics) like you could piggyback the
> second 2mb on top of the first without much wiring.
> piggyback sockets needed, of course (anyone still make them?).
> 
> -- 
> Andrew Hay		+------------------------------------------------------+
> Holistic Specialist	| I will design a computer for you, so powerful that   |
> AT&T-BL Ward Hill MA	| organic life will form part of its operational matrix|
> mvuxq.att.com!adh	+------------------------------------------------------+

I have been thinking the same thing, but I don't have schematics to
fill in the details.  A long time ago, I piggy backed 16k RAM chips
( it was a very long time ago :-) to bring a 16k TRS-80 color computer
to 32k.  Of course I had to redirect an address line to each chip with a
jumper, but would a simular technique work to bring a 2MB 3B1 to 4MB.

If anyone has done this before with a 3B1, I am sure the rest of us would
like to hear about this.

Mike Thompson

---------------------------------------------------------------------------
Michael P. Thompson                      FOCUS Semiconductor Systems, Inc.
net: (sun!daver!mfgfoc!mike)             570 Maude Court
att: (408) 738-0600 ext 370              Sunnyvale, CA  94086 USA
---------------------------------------------------------------------------