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From: mvadh@cbnews.ATT.COM (andrew.d.hay)
Newsgroups: comp.sys.att,unix-pc.general
Subject: Re: Call for Help:  3B1 1MB to 2MB upgrade
Keywords: Any hardware gurus out there?
Message-ID: <2653@cbnews.ATT.COM>
Date: 16 Dec 88 11:47:48 GMT
References: <803@ttrde.UUCP>
Reply-To: mvadh@cbnews.ATT.COM (andrew.d.hay)
Organization: AT&T Bell Laboratories
Lines: 37

In article <803@ttrde.UUCP> pfales@ttrde.UUCP (Peter Fales) writes:
>Here's one for you hardware experts.  I have been trying to upgrade my 3B1
>from 1MB on the system board to 2MB.

[]

>The system now boots and runs fine, but it doesn't recognize the extra
>memory.  Is there anything more I have to do?  Assuming I have done 
>all that is required, how can I go about testing the thing?  As far
>as I can tell, the diagnostic disk can not test any memory not
>recognized  at boot time.

i did this last summer, with the same results.
as far as i can tell, it looks like the motherboard needs some jumper
wires added to steer signals to their new destinations.
i haven't had time to try to match the schematics (which don't seem to
correspond with the latest motherboard revisions) to my computer.

i did try switching the 64k-256k chip jumper, and my machine dropped
to 512k ram.

we have 2Mb 3b1s at work, and i've gotten a good look at the 2Mb
motherboard, without enlightenment, though i didn't have my
motherboard side-by-side for comparison.

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?).

>As they say, thanks in advance,

Ditto (i mean, 'ditto', not 'Ditto', mike)

-- 
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	+------------------------------------------------------+