Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!shadooby!samsung!think!mintaka!bloom-beacon!eru!luth!sunic!mcsun!ukc!acorn!moncam!emmo
From: emmo@moncam.co.uk (Dave Emmerson)
Newsgroups: comp.sys.ibm.pc
Subject: Re: yo mother
Summary: I did it my way...
Message-ID: <348@marvin.moncam.co.uk>
Date: 5 Jan 90 12:39:29 GMT
References: <20726@kuhub.cc.ukans.edu>
Organization: Monotype ADG, Cambridge, UK
Lines: 42

In article <20726@kuhub.cc.ukans.edu>, ARRITT@kuhub.cc.ukans.edu (What a waste it is to lose one's mind.) writes:
> I've seen some discussions in this group about replacing motherboards.
> A recent issue of "PC" magazine has ads for 286 motherboards for about
> $250 or so.  This seems like a very attractive alternative to buying
> a whole new system.
> 
> My question is: what is involved in replacing the motherboard?  That is,
> [deleted for brevity]
> Also, how well do these things match up, physically?  Will a "typical" 
> 286 motherboard fit into a "typical" XT-clone case, without a lot of 
> drilling into metal and so forth?
> [more deleted]

There are so many clones about in so many styles that there is no clear
cut answer. This is a summary of my own experience with a '286 / 20
motherboard, AMI BIOS, NEAT chipset, into a Tandon PC case..
I bought the board locally, so I was able to check the physical dimensions
first. Not closely enough though, I had to slacken the power supply fixing
screws, and squeeze it over by 1mm to use one of the original pcb
suports. All the rest were removed and replaced with plastic self-adhesive
supports. The one metal one was retained for the chassis-pcb ground
connection. There was a folded metal reinforcement bar across the floor
of the case which I had to remove to get the new motherboard to fit under
the disk drive cage. The case is still rigid enough without it. The 
power connections were in a different sequence, I removed all the crimpon
connectors from the shell, and reinserted them in the right order. Check
the colour/voltage protocol on yours while the old board is still in,
smpu's can give weird readings with no load on them. They're only +-5
and +-12, it's quite safe.
One of the 16 bit slots can only be used with an 8 bit card because it's
too close to the disk drives, and I had to rewire the power and turbo
led's for new connectors, but that was all there was to it. I'd guess
that this would be about an average installation, doubtless some
combinations could be easier, and some harder.
The improvement was well worth the time and money. From your self-appraisal
I'd say you could do it too, but bear in mind I do this sort of thing all
the time as part of my job, and I can't afford the fare to come and help
out if you have problems.

ATB,

Dave E.