From: wbarnes@sura.net (Bill Barnes)
Subject: Motherboard Info: Summary
Organization: SURAnet, College Park, MD, USA, NA, Earth, Milky Way
Date: Wed, 29 Jul 1992 19:22:41 GMT

As promised, here is my summary of all the informartion I received
on upgrading motherboards (and a little bit about upgradable motherboards).
Again, profuse thanks to everyone who sent me info.  Thank you all!

--------------------------------cut here-----------------------------------

From: Bob Wilson <wilson@math.wisc.edu>


It really can be that simple, if (a) all goes well and (b) the
previous installation was well done. I suggest you look at one of the
"build your own PC" books available at most book stores. They will
show how to install a motherboard. Since you probably don't have much
documentation on the case and its wiring, take notes on where the
various cables go. If you have documentation on the old MB, or if it
is well labeled, that will let you figure out which plug comes from
the reset switch, which from the keyboard lock, etc. If you don't have
such documentation you will have to trace the wires back to the
switches or LED's they connect to on the panel.
Power connectors are pretty much standardized among 286 and later
machines except for some wierdos from AT&T and other big names: In
this case you are better off the less-well-known is the manufacturer
of the old system!
Bob Wilson
wilson@math.wisc.edu

---------------------------------------------------------------------------

From: nummi@drill.me.utoronto.ca (Matti Nummi)


In comp.sys.ibm.pc.hardware you write:

>A friend of mine owns a 286-12 and wants to upgrade to a 486.  One option
>he's considering is replacing the motherboard so he can still use all
>his old hardware (HD, floppy, monitor - everything but the memory).

>If we take this option, we're hoping it'll be fairly straight-forward:
>take out the old motherboard, screw in the new one, pop the cards back
>in, and - Voila! - you're ready to go.  Somehow, though, I suspect it will
>be more difficult than that...

>Bill "Whassamatter?!  Can't you take a joke?!" Barnes   wbarnes@sura.net

	I don't think that you will have any trouble just swapping the 
motherboards.  I have done the following upgrades, all different boxes,
	clone XT (8088)  -->  no-name 386SX-16
	IBM AT  (80286)  -->  no-name 386SX-20
	no-name 386DX-20 -->  no-name 486DX-33
and I have yet to encounter a problem.  The only concerns are to make sure
that the new motherboard fits your case and the leads from your power supply
are the same as what the motherboard wants.  The power supply question is
(usually) only relevant for some old XT power supplies which did not have
a "power good" signal.
	All the old cards work fine with the new motherboards, at least 
they have worked fine in my experience.
	Go ahead and try it, it really is as simple as you hope, and you
don't have to know more than driving the new screws and attaching the
power leads.

	Matti Nummi		nummi@me.utoronto.ca

---------------------------------------------------------------------------

From: CHE358W@vaxc.cc.monash.edu.au


>From: wbarnes@sura.net (Bill Barnes)
>Subject:How do you replace a motherboard?
>Date: 23 Jul 92 19:25:30 GMT
>Message-ID:<1992Jul23.192530.16445@sura.net>

>[Let's try a different approach to this problem, since my last attempt
>got me zip...]
>
>A friend of mine owns a 286-12 and wants to upgrade to a 486.  One option
>he's considering is replacing the motherboard so he can still use all
>his old hardware (HD, floppy, monitor - everything but the memory).
>
>So the question is, how does we replace it?  Does anyone have suggestions,
>tips, advice, whatever on where - and what - to look for a new motherboard,
>how to swap boards and equipment, etc.?  Any magazine articles or books
>on the subject out there?  Any big pitfalls we should be aware of?
>If we take this option, we're hoping it'll be fairly straight-forward:
>take out the old motherboard, screw in the new one, pop the cards back
>in, and - Voila! - you're ready to go.  Somehow, though, I suspect it will
>be more difficult than that...
>
>As always, many thanks in advance for any advice given.  E-mail would
>be appreciated; I'll summarize if there's interest.
>--
>Bill "Whassamatter?!  Can't you take a joke?!" Barnes   wbarnes@sura.net
>Disclaimer:  The author apologizes for any thought-provoking material he may
>            have accidentally included and promises not to do it again.
>Datclaimer:  My employers wouldn't WANT to share some of my opinions.
Hi,
  I'm afraid I can't tell you about sources for components 'cause I'm an Aussie.
But my father replaced our 286-16 with 386-25 motherboard and it was so easy
even my father (who is not very technically literate) could do it. You have
to configure you cmos of course. One problem we did have was we had to get
a new box 'cause the boards were arranged differently so some sticky up bit
on the new one (the memory I think) wouldn't fit under the power supply. Our
box was Australian so it was probably non-standard.
  Have you thought that once you upgrade to a 486 you'll want a bigger disk, a
better screen, a ...
Have fun.
Samantha Lane
che358w@vaxc.ccmonash.edu.au

---------------------------------------------------------------------------

From: tmcreek@eos.ncsu.edu


In article <1992Jul23.192530.16445@sura.net> you write:
|>A friend of mine owns a 286-12 and wants to upgrade to a 486.  One option
|>he's considering is replacing the motherboard so he can still use all
|>his old hardware (HD, floppy, monitor - everything but the memory).
|>
|>So the question is, how does we replace it?  Does anyone have suggestions,
|>tips, advice, whatever on where - and what - to look for a new motherboard,
|>how to swap boards and equipment, etc.?  Any magazine articles or books
|>on the subject out there?  Any big pitfalls we should be aware of?
|>If we take this option, we're hoping it'll be fairly straight-forward:
|>take out the old motherboard, screw in the new one, pop the cards back
|>in, and - Voila! - you're ready to go.  Somehow, though, I suspect it will
|>be more difficult than that...
|>

Ok.  This is a tough question not being there, but I have done this 
three times (going for four soon).  

Some of the later 286-12's came on VLSI motherboards that were
about 10 inches square.  If the case only fits it (no extra room)
you will need a new case.  Some places in Computer Shopper 
sell "bare bones systems" with just a case and MB.  This could
be an option.

Barring that, it's as easy as you say, just don't let it know 
you are afraid.  Remove the old motherboard.  There are probably
a few screws (at least one) and some plastic clips.  The clips
have knobs under the board that fit into slots on the 
case's bottom panel (at least on mine).  Remove the MB, observing
static discharge procedures (ground yourself to a case with the 
power cord hooked up.  You don't have to worry as much if the 
room is humid.  

Pull the new motherboard out of it's bag (static check first).  
I always insert the plastic clips first, so you just drop it in and 
slide the tabs into the case slots.  Hook up the power connector
(the two black wires go together; you'll see what I mean).  Mount
the motherboard with at least one screw that connects to the case.
Make sure it goes through one of the metal plated holesin the MB
Now you need to read the manual to find out where the power and
turbo LED's hook up, the turbo switch, keylock, speaker, etc.
Set any jumpers it says to set (bus speed, etc.)  

Now, put the cards back in and hook up the HD light to the 
controller (if applicable).  Boot the machine with the lid OFF, 
so you can power down and make any changes quickly.

I have only paraphrased here, so I may have left out steps 
(like adding the memory), but I am fairly sure I have included
the critical things (like the grounding screw).

Good luck.
--
Send replies to:               | My opinions do not represent
     tmcreek@eos.ncsu.edu      | anyone who does not feel the
     creek-tm@aza.csc.ncsu.edu | same way about it as I do.

 ----------------------------------------------------------------------

From: ath@linkoping.trab.se


In article <1992Jul23.192530.16445@sura.net> you write:

>So the question is, how does we replace it?  Does anyone have suggestions,
>tips, advice, whatever on where - and what - to look for a new motherboard,
>how to swap boards and equipment, etc.?  

I think there's a book 'How to upgrade your PC' or something like
that.  Don't know if it's any good, though.

>If we take this option, we're hoping it'll be fairly straight-forward:
>take out the old motherboard, screw in the new one, pop the cards back
>in, and - Voila! - you're ready to go.

Yes, almost. The usual precautions apply - you probably know them
already.  Here's the most important:

You have to ensure that the new motherboard will fit in the old box.
Most manufacturers provide a paper template of the motherboard so you
can check if it fits, where the fastening holes are. You can usually
also see where the various connectors are - in some cases you may need
to get longer cables.

New motherboards may have diskdrive and VGA onboard. If you want to
use your old cards, ensure that the on-board controllers can be
disabled. Alternatively, ensure that the disk controller works with
the disk type you already have.

If you're buying from a good dealer, they may even have a booklet
that describes the installation. Ask for one before buying.

Also check that your power unit can handle the new motherboard.

Check that you have memory for the new motherboard - if you're
changing from a very old one, it probably uses DIP chips, while most
modern boards use SIMMs.

Before you switch, write down the old setup info, or save it to disk
or something.

Label *all* connections clearly before you remove them. It can be hell
putting things back otherwise. Also check if connectors can be put
back the wrong way - most cannot, but in a few cases they can. If they
can, make sure you know which way is right.

Don't connect more than one card at a time when you're trying to get
things going again. Start with only monitor and keyboard connected,
and then add one card at a time.

If you're planning to run OS/2, check and double check with the
manufacturer that the board can do it. If possible, ask to see one run
OS/2.  OS/2 is 'stressful' and gives particularly the memory a tougher
workout than DOS does. Some motherboards are too noisy to cope with
OS/2, although they may run DOS beautifully. Some SIMMS (particularly
the 3-chip ones) can help push an already noisy motherboard over the
edge. The same goes for most versions of UNIX.

Hope this is of any help,

-- 
Anders Thulin       ath@linkoping.trab.se 
Telia Research AB, Teknikringen 2B, S-583 30 Linkoping, Sweden

---------------------------------------------------------------------------

From: Chris Stratford <CS%IBM-B.RUTHERFORD.AC.UK@ib.rl.ac.uk>


In most cases, you can just take everything out of the box, unscrew the old
board and put in the new one.  End of story.

But...

Some PCs have slight differences.  The expansion slots in Tandons aren't in
the same place as everyone elses (some are sideways, which really buggers
things up,) others may also have this problem.  Another possible problem
is power supply connectors, there appear to be two major types, you will
nee to check this.

On the whole, things are relatively simple.  You may need to take a hacksaw
to part of the inside casing, or change a connector to something else, but
that's about it.

Hmm, that's a bit vague, but the best I can manage at the moment.  Good
luck with the conversion.

    Chris.
    (cs@ib.cc.rl.ac.uk)

----------------------------------------------------------------------------

From: RCG1597@ZEUS.TAMU.EDU


In article <1992Jul23.192530.16445@sura.net>, you write...

>So the question is, how does we replace it?  Does anyone have suggestions,
>tips, advice, whatever on where - and what - to look for a new motherboard,
>how to swap boards and equipment, etc.?  Any magazine articles or books
>on the subject out there?  Any big pitfalls we should be aware of?
>If we take this option, we're hoping it'll be fairly straight-forward:
>take out the old motherboard, screw in the new one, pop the cards back
>in, and - Voila! - you're ready to go.  Somehow, though, I suspect it will
>be more difficult than that...

	Actually, it's not a whole lot more difficult than that.  As
for shopping for one, there's a number of different options.  You can
check with Computer Shopper, keep your eyes open on the net, or go to
your local shop.  The net and Comp Shopper are usually the cheapest.
I got a 386-40 from someone on the net awhile back (he was a
small-time dealer in CA, even though I don't think thay are
technically supposed to be advertisiusing on the net) for a very cheap
price.  It was brand-new and still sealed for $225.  So it's basically
a case of how much you are willing to pay and what you feel safe with.
I f you are really worried that a board will be bad, it's best to stay
with a local shop, even though they are usually more expensive.  In
any event, if you have a credit card, then use t when you buy the
board, this gives you added protection if something goes wrong.
	As for the installation part, as long as the board has the
original documentation, it's a breeze.  Hust keep in mind that boards
usually do not come with memory and that it must be installed before
operation.  The only real caution I can make about installation is to
use an anti-static mat and cuff.  Static electricity is capable of
trashing a board.  I have been told that static electricity can even
cause "infant mortality" where the computer works fine for a little
while and then dies.  This is often mistaken as a malfunctioning board
when in reality it was poor installation attention.

Hope this helps!

-Rick

-----------------------------------------------------------------------------

From: toy@alydar.crd.ge.com (Raymond L. Toy)


In article <1992Jul23.192530.16445@sura.net>, you write:
|> [Let's try a different approach to this problem, since my last attempt
|> got me zip...]
|> 
|> A friend of mine owns a 286-12 and wants to upgrade to a 486.  One option
|> he's considering is replacing the motherboard so he can still use all
|> his old hardware (HD, floppy, monitor - everything but the memory).
|> 
|> So the question is, how does we replace it?  Does anyone have suggestions,
|> tips, advice, whatever on where - and what - to look for a new motherboard,
|> how to swap boards and equipment, etc.?  Any magazine articles or books
|> on the subject out there?  Any big pitfalls we should be aware of?
|> If we take this option, we're hoping it'll be fairly straight-forward:
|> take out the old motherboard, screw in the new one, pop the cards back
|> in, and - Voila! - you're ready to go.  Somehow, though, I suspect it will
|> be more difficult than that...
|> 

Bill,

I did exactly this a few months ago.  It went pretty much as you said.  The
only gotcha is knowing how to connect all of the little wires like the
speaker, CMOS battery, harddisk LED, turbo button, reset button, etc.
I didn't know how so I just guessed and hoped nothing blew up.  Nothing
did up, even though I did connect some of the backwards.  

Except for that, I just took out the old motherboard and dropped in the new.
Oh, except that while I was at it, I wanted a new mini-tower case.  I also
got a new disk drive, but I could have used my old ones.

Good luck if you decide to take this route!

Ray
Toy---->toy@soho.crd.ge.com

-----------------------------------------------------------------------------

From: faruque@sun.soe.clarkson.edu (Abdullah Faruque)


wbarnes@sura.net (Bill Barnes):
> [Let's try a different approach to this problem, since my last attempt
> got me zip...]
> 
> A friend of mine owns a 286-12 and wants to upgrade to a 486.  One option
> he's considering is replacing the motherboard so he can still use all
> his old hardware (HD, floppy, monitor - everything but the memory).
> 
> So the question is, how does we replace it?  Does anyone have suggestions,
> tips, advice, whatever on where - and what - to look for a new motherboard,
> how to swap boards and equipment, etc.?  Any magazine articles or books
> on the subject out there?  Any big pitfalls we should be aware of?
> If we take this option, we're hoping it'll be fairly straight-forward:
> take out the old motherboard, screw in the new one, pop the cards back
> in, and - Voila! - you're ready to go.  Somehow, though, I suspect it will
> be more difficult than that...
> 

Yes, it is pretty much straight forward as you described. But consider
the following things when replacing a motherboard:

1. The size of the new motheboard should be same or less than the
existing one. They come in FULL size, BABY AT size, MINI size. So,
select the one that will fit in the existing case. Some non-standard
case may not be able to take any standard clone motherboard. In that
case you may have to buy a new case.

2. A 486 board needs proper cooling, so if your case is very small
and compact then probably it is a good idea to buy a bigger size
case with proper vetilation.

3. All your existing cards (like video, HD/FD controller, I/O etc.)
should work fine as long as you set the BUS speed of the new BOARD
at 8Mhz (which is standard AT BUS speed). Almost all new 486 motherboard
will allow you to change the BUS speed higher than 8Mhz to get better
performance. If you select any thing above 8Mhz than some of your
old card may not work. You must buy new cards that can operate at
the desired BUS speed.

4. Please discharge the static electricity from your body while
changing the motherboard. You can do it by touching any metal part
which is grounded. 

Hope that helps.

-Faruque
Email: faruque@sun.soe.clarkson.edu

---------------------------------------------------------------------------

From: fritz@ra.csc.ti.com (Fritz Whittington)


In article <1992Jul23.192530.16445@sura.net> you write:
>So the question is, how does we replace it?  Does anyone have suggestions,
>tips, advice, whatever on where - and what - to look for a new motherboard,
>how to swap boards and equipment, etc.?  Any magazine articles or books
>on the subject out there?  Any big pitfalls we should be aware of?
>If we take this option, we're hoping it'll be fairly straight-forward:
>take out the old motherboard, screw in the new one, pop the cards back
>in, and - Voila! - you're ready to go.  Somehow, though, I suspect it will
>be more difficult than that...
Actually, it really isn't much more difficult than that.  The best
help would be if you can contact a local PC computer club, because
there's just nothing like having local info on the best buys, and a
little advice.
The one thing that you might have mechanical trouble with is the
location and size of the mounting holes to position the motherboard in
the box.  One suggestion is that you consider buying a motherboard and
enclosure/power supply together.  The extra case/power supply may cost
you $50-80 or so, but the 286 case/powersupply is probably showing its
age by now, and may not have as much power available as you need to
run a 486.  Finally, this will make it much easier to sell the old 286
motherboard, if still in its case.  


-- 
Fritz Whittington     Texas Instruments, 12840 Hillcrest #200, Dallas, TX 75230
fritz@csc.ti.com                Office: +1 214 917 7437    FAX: +1 214 917 7487
_Since I am not an official TI spokesperson, these opinions contain no spokes._

--------------------------------------------------------------------------

From: SLB1B@CC.USU.EDU


>From: wbarnes@sura.net (Bill Barnes)
>Subject:How do you replace a motherboard?
>Date: 23 Jul 92 19:25:30 GMT
>Message-ID:<1992Jul23.192530.16445@sura.net>

>[Let's try a different approach to this problem, since my last attempt
>got me zip...]
>
>A friend of mine owns a 286-12 and wants to upgrade to a 486.  One option
>he's considering is replacing the motherboard so he can still use all
>his old hardware (HD, floppy, monitor - everything but the memory).
>
>So the question is, how does we replace it?  Does anyone have suggestions,
>tips, advice, whatever on where - and what - to look for a new motherboard,
>how to swap boards and equipment, etc.?  Any magazine articles or books
>on the subject out there?  Any big pitfalls we should be aware of?
>If we take this option, we're hoping it'll be fairly straight-forward:
>take out the old motherboard, screw in the new one, pop the cards back
>in, and - Voila! - you're ready to go.  Somehow, though, I suspect it will
>be more difficult than that...
>
>As always, many thanks in advance for any advice given.  E-mail would
>be appreciated; I'll summarize if there's interest.

Please summarize!  I'd be interested to see if there are any pitfalls to watch
out for.  I've upgraded a couple of friend's computers in the exact manner that
you've described, and have had great success.  Everything went smoothly. We
just followed standard safety precautions about static electricity, etc. I just
did my machine, except that I needed a new case since the old one wouldn't
accept a now-standard motherboard.  Now I have a nice 386SX zipping along, and
they have 486's (I don't have the extra money for a 486 yet. :-(   )

The main thing that I would stress is MAKE SURE YOU'RE GROUNDED THROUGH A 
1 MEG-OHM RESISTER! And UNPLUG THE COMPUTER! Grounding yourself via wrist strap
is a protection for the computer so you don't zap anything.  The meg-ohm
resister is for your protection.  You don't want your body to be completing any
circuits.  I ignored that precaution until about a year ago when  I got a
really good jolt connecting two  pieces of equipment that were in different
rooms. It wasn't serious, but I could have ruined some componants and myself.
If you can find anti-static foam, USE IT! That can save your boards when
they're not in use.

The only thing that I've found that may affect performance is the fact that 
some of our old cards aren't as zippy as the ones you can buy today, and also I
haven't swapped any 8-bit boards for 16-bit boards. But, I've gone up to a
Landmark rating of 19, and I'm pleased with the performance. I don't do
windows, but would get a nicer video card if I could stand using windows.

I've got a cataloge from a company that doesn't sell to the public, though  
I can buy from them because I've a business licence (I do software on the
side). My normal job is managing a few computer labs and doing repairs and
maintenance on the equipment. The prices aren't incredible, and you might 
be able to find a better deal out of Computer Shopper. I mainly get 
miscellanea from them (floppy disks, drive cleaners, etc.).

I did my friends' computers  as a side thing, and could pass a motherboard on
to you for my cost, too.  Also, local computer stores may be able to sell you
a motherboard.  The ones around here aren't too badly priced, but we could get
them slightly cheaper, even with shipping figured in.

If you could let me know of any places that have better prices than I can get
them for, my pocketbook would appreciate it!  I'd really like to get a 486-50,
but I've got a family to feed in addition to the computer :-)

Anyhow, these are the prices including shipping (rounded off to the nearest
dollar) that we've found:

386SX-25 = $182 (Intel CPU)
386DX-33 = $302 (Intel CPU)
386DX-40 = $302 (AMD CPU)
486SX-20 = $467 (Intel CPU)
486DX-33 = $675 (Intel CPU)
486DX-50 = $943 (Intel CPU)

-------
James Knowles
slb1b@cc.usu.edu
Disclaimer: No, none of this has to do with my employer, so stuff it!

---------------------------------------------------------------------------

From: stella@gandalf.rutgers.edu (Ricky Suave Stella)


>If we take this option, we're hoping it'll be fairly straight-forward:
>take out the old motherboard, screw in the new one, pop the cards back
>in, and - Voila! - you're ready to go.  Somehow, though, I suspect it will
>be more difficult than that...

That's it! That's all there is to it.

Your I/O card, the video card and FD/HD controller will work on your new board.
The only thing will be memory boards (if you have any) those are no good.

But that's it.  and make sure you are grounded when you do the swap.  The
last thing you want is a static discharge on the boards.  you'll have none
after that!


-- 
------------------------------------------------------------------------------
 Ricardo Stella			Summer ONLY E-mail ----> rickys@hound.att.com
 Inbound Services		All Time E-mail -> stella@gandalf.rutgers.edu 
 HO 2B-603 - (908)949-3049      ...suave...	       AT&T Bell Laboratories

---------------------------------------------------------------------------

From: STRAUSS@UNCA.EDU


Some current pc magazines have described the 486sx. Also, see
Scott Meuller's new book, Upgrading & Repairing PCs (1992 or 1991 ed.).
Basically, a 486sx will allow you to add a full 486 chip at a later
date (the upgrades just came out and are over $500 now). The result
will be you'll get 70% of a full 486 DX. Don't ask me why it isn't a
full 100%, but hey, in a couple of years, the chip should be about $100.

Get a machine with a slop for the upgrade. It "shuts down" the old chip,
although in some systems, you exchange them.  Best deal today.

Bob Strauss

-----------------------------------------------------------------------------

From: rogers@ficc.ferranti.com (keith rogers)


It's really not much more difficult than that.  However, you'll want
to make sure that you do a full backup (and verify it!) before you do
this exercise.  It may be that the new board/bios may not have the
same drive geometry setup for the hard drive, or who knows what else
can go wrong, and you'll end up booting from floppy, doing an FDISK,
FORMAT, etc. on the hard drive (this happened to me).

N.B. The store where I got my motherboard does the installation for $30.
If you're the least bit squeamish, or don't want to have to deal with
the problem of what happens if the mb is bad, and the store claims you
broke it, that's pretty cheap compared to the price of a new 486 mb.

Also, be prepared to buy at least 8M of RAM, and expect to fork out for
a new hard disk, unless you've already got a 100M IDE or better.  If the
286 is using a 40M MFM or so, you'll be out of space in a hurry, and
the performance is really going to bottleneck the 486.  Then, if its
got EGA (or worse), you'll probably want to upgrade it sooner or later.
At that point, the do-it-yourself upgrade will have cost more than the
price of a new PC, and it will still have the old power supply, floppies,
case and keyboard.  (This is my experience.)  Tell your friend to think
a long time about what he's getting the system for, and what he's going
to ultimately need.  It may be cheaper to bite the bullet now, and get
a whole system.  Then he can sell or donate the 286, or keep it in the
closet for when disaster strikes.

Just my 2 cents.
--
Keith Rogers     (rogers@ferranti.com)      |  **** STANDARD DISCLAIMER ****
Ferranti International Controls Corporation |  Guitars, Cadillacs, hillbilly
P.O. Box 5012, Sugar Land, Texas 77487-5012 |  music, the only things that
(713) 274-5592                              |  keep me hanging on....

---------------------------------------------------------------------------

From: bet@cyclone.sbi.com (Bennett E. Todd)


Cut from some email I sent someone else:

Doing a motherboard upgrade on an IBM AT is a piece of cake; I just did it.
Pull the motherboard before you go shopping and take it with you, and you
can compare the locations of the standoffs and connectors to ensure the
replacement will go in perfectly. To pull the motherboard you open the case,
remove the I/O boards, remove the cables (including the keyboard connector)
that attach to the motherboard, then slide the motherboard about 1/2" away
from the power supply, which releases keyhole-lock heads on the standoffs.


I upgraded an IBM 5171 PC-AT (6MHz 80286, the Original:-) to a 386SX-25 with
_no problems_. It went perfectly.

-Bennett
bet@sbi.com

-----------------------------------------------------------------------------

From: Dennis Gellert <GELLERT@janus.trl.oz.au>


>A friend of mine owns a 286-12 and wants to upgrade to a 486.  One option
>he's considering is replacing the motherboard so he can still use all
>his old hardware (HD, floppy, monitor - everything but the memory).
>
>So the question is, how does we replace it?  Does anyone have suggestions,
>tips, advice, whatever on where - and what - to look for a new motherboard,
>how to swap boards and equipment, etc.?  Any magazine articles or books

Bill,
I have replaced quite a number of motherboards in a variety of
machines. And yes, it is generally quite straight forward and well
worth considering in most instances.  This is because the defacto
standardisation on the PC components is quite good.  As far a buying a
new motherboard, simply go for something with the price / performance
you are looking for. Whether its a 386sx-16 or a 486-50, it makes no
difference to the upgrade procedure. All 386DX & 486 ISA boards I have
seen are the standard baby AT board size.

Normally, you just need to dismount the expansion cards and unscrew the old
motherboard, screw the new motherboard in place (everything should line up),
replace expansion cards, and run setup. All done.

Pitfalls I have struck.
1. Not all old motherboards adhere to the defacto physcal standard. May need
   to drill a few new mounting holes and use 6mm spacers. This happens with
   some old giant size motherboards.

2. Occasionally, (rarely) the old ST-506 AT Hard/Floppy disk controller card
   would not work reliably in the new motherboard. Would lock up the system at
   times.  Did solve this problem by moving a jumper on the controller
   card. (compatible with the new bus speed or something).

In summary, if the AT has a "standard" size motherboard, good hard disk and
expansion cards, it is worth upgrading and should not have any problems. This
applies to the common ISA systems. EISA & Microchannel are different. And yes
new memory.

Cheers, Dennis Gellert

---------------------------------------------------------------------------

From: mbb@cbnewsb.att.com


wbarnes@sura.net (Bill Barnes):
....
> If we take this option, we're hoping it'll be fairly straight-forward:
> take out the old motherboard, screw in the new one, pop the cards back
> in, and - Voila! - you're ready to go.  Somehow, though, I suspect it will
> be more difficult than that...

I've had three different motherboards in my desktop XT clone, and it's
been a little more difficult than that, but nothing insurmountable.

1. I've had two different size boards, but the bolt holes are all in
the same places, but on the other hand the hardware is not always in
the same bolt holes.  Once I had to fabricate a makeshift standoff.

2. The wires for various panel lights and switches don't always
connect to the same place on the board, and different boards don't all
have the same access points.  For instance, the board I'm using now
does not have a connection for the power-on LED.

All these boards have V20 CPUs, but differ in speed and memory.  For
more sophisticated swaps, like changing a digit in the CPU, there may
be bigger differences.

							Marty
marty@hoqaa.att.com		hoqaa!marty
Martin B. Brilliant		(Winnertech Corporation)	

-----------------------------------------------------------------------------

From: dougm@pnet51.orb.mn.org (Doug Mcintyre)


It generally is as easy as that. Make sure you haven't got anything strange or
weird that is nonstandard (ie. Packard Bell's cases will only fit Packard
Bell's motherboards) generally the better brands tend to be standard. Its
pretty hard to drill and mount new holes in the case to support a standard fit
motherboard :) Generally 99% of them out there are standard. 

Memory, like you said, will have to be all brand new.

There are lots of books on builing your own PC system. Personally, I've never
opened one, but I'd guess it would be a good hand holder.

Keep static electricity down at all times. Pro's use a grounding strap (ie.
wrist-band with a clip on cord) available at all hobbiest electronic stores.
If you're touching metal at all times, you'll be okay though. 

You do generally have to mess with the connectors a little bit. Nobody in the
world is standard on connectors it seems, but you get 80% of them okay. 

Other than that, it should be a piece of cake.

UUCP: {tcnet, crash}!orbit!pnet51!dougm
ARPA: crash!orbit!pnet51!dougm@nosc.mil
INET: dougm@pnet51.orb.mn.org                                GENIE: D.MCINTYRE1

--------------------------------------------------------------------------

From: "MICHELLE HURT" <mdh@swlrd8.msd.ray.com>


HI THERE-

I've been busy so haven't been on the net-but here goes.  I've upgraded
2 8088's so I'll give a listing of my trials and tribulations.  And will
be doing my third in about one week.

There are four things you should consider about the case and powersupply.
First - is the case standard (or close to it) or is it a
custom jobbie.  One of my upgrades consisted of a Leading Edge Modle D-
whose case is a real custom job.  If it is a custom case-you may be
better off getting a new case and powersupply.  (or be real good with
redoing everything in the case like moving powersupplys, and drilling
new case holes, ect..)  If it looks similar to other cases (like in
the ads for cases) then it's probibly okay.
Second - how big is the power supply? and what do you plan to
do with the computer in say 1 year? or 2 years? (add new harddisks, add
CD rom, add tape drives ect) if It's a 150w, plan to get a new powersupply
expecially if your going to add a lot in the future.  Maybe a new case so
you have the slots available.  The Leading Edge only had room for 2 half
hight drives - so yet another reason for a new case...
Third - your expansion slots are how far apart? 3/4 inch or 1 inch
about?  If 1 inch get a new case - 486's expansion slots are 3/4 inch
apart.  Yours should be 3/4 inches too - only older 8088's are an inch
apart I found.  but check to be sure.
Fourth- Check to see how the powersupply connects to the mother board.  
It should be two connectors real close together (may even look like 1 
connecter)  But if the connectors are not standard, you'll need to
either get a new case or rewire the connectors.  Every one I've seen
(Leading edge and Eagle) where the case and power supply's were custom
built, still used the same connectors on the motherboard.  So this is not 
a big worry, but one to consider.

Okay, so now the new motherboard should fit in the case.  (or you've
got a new case) Try to find a motherboard that will fit in the mini-AT
cases.  Thats a smaller board then standard to help insure the fit.

Before you do anything, make sure your grounded.  486's, and 286's do
not take shocks from static to well.  Touching the case should do it,
but if your really conserned, take a strip a wire bare at both ends,
but not in the middle, (long enought to work around) and attach one
end to the case and the other to your wrist (make sure some of the
bare wire touches your wrist).  I use an anti- stat mat, but in
emergency's (read laziness) I just hook myself to the case.  And
sometimes not even that. (I do all the fiddling with the hardware at
home)

Open the case, and carefully remove all cards and drives.  Check any
cards to see if they'll work in the new machine.  Specially build
cards may not.(I mean the 286 manufacturer built for that 286 only)
Also you'll need replacement cards for anything built into the 286
motherboard.  Like the Leading Edge Modle D had IO, and the Floppy
controllers built in.  We had to buy a new cards for those functions
on the 386sx-16.  Then unplug all wires from the 286 motherboard.

The 286 motherboard will be held in by some small screws and plastic
doodads.  Undo all the screws untill the board is loose then slide to
the right and lift out.

Your new mother board will come with instructions on how to install
it.  Set the correct jumpers and stuff.  If it didn't come with
documentation, get some sent to you from the manufacturer - you'll
need it.

Before I put the board in, I install the memory, and plug everything
in and test it.  I do this, cause if I set a jumper wrong it's easier
to fix then if it was in the case.  Make sure the motherboard is
resting on non metal material you dont want to short it out.  But once
it works I disconnect the cards and install the motherboard and then
reinstall all the cards and drives.  Before i put the cover on I do
one last test to make sure it works.  (Turn it on, and test
Everything).

If your using the original case, you'll want to make sure it can
handle the cooling needs of a 486.  This is expecially true if it's a
custom case.  If the CPU is in about the same spot as the 286 CPU then
theres less worry- but if it's in a new spot, you may need extra
cooling power.  Or if things are really packed in there (like lots of
cards and drives and cables) you should consider added cooling.  One
(not elegant but cheap) solution is to buy an electrical fan (local
electrial shop should sell them- about the same size as in the power
supply) and some window/door insultaion strips (you know the strips of
foam with tape on one or both sides).  Put the insulation around the
outside of the fan and put the fan over a vent on the case.
Preferably one near the cpu.  The fan should plug into a wall outlet
(you may have to wire the plug in, but make sure it can handle AC
current) It's ugly and noisy but works and is cheap.  We had to do
this to cool the harddisk on my old Eagle 8088 PC. (It kept
overheating)

A Couple other things - not directly related to the mother board
replacement, but something to consider.  First, you'll fill the
harddisk sooner then you think.  When we upgraded my brothers 8088 to
a 386sx-16 we kept his old harddisk (a 40 meg MFM).  There was of
course a great improvement in speed, but it didn't take him two months
to cram the disk full.  We got super stor (or something) and dug out
an old 20 Meg MFM.  Those combined he had close to 100 meg of disk
space.  (Which is now filled) And second (expecially if it's MFM or
RLL) the slow older drives will drive you up the wall.  The MFM's
noticably slow down my brothers 386.  (we hooked up my SCSI for a test
run and the 386sx-16 was noticably faster) It's mainly the difference
between 15ms access time and 28 ms access time.  For a joke we hooked
the MFM to my 486-33 and it was like my 486 hit a brick wall.
Expecially on any disk extensive programs.

Finally - deck it out with all the RAM you can.  8 meg at the least.
If your running DOS you can use the extra as a disk cache.  If your
running windows or os2 the more RAM the better.  My 486 is at 12 meg
and windows just cruises.

Don't worry, installing the motherboard will be easier then you
thought.  Just go slowly.

Now, if your just going to toss the 286 motherboard, may I recommend
something?  Buy some clock hands (around 8 dollars), drill a hole in
the motherboard somewhere and put the clock parts in.  Makes a great
clock to hang on the wall.  I've done that with several of the old
computer parts I have lying around.  They make great gifts too.

Michelle Hurt
mdh@swlra1.msd.ray.com

--------------------------------------------------------------------------

From: trekkie@netlink.cts.com (Bryce Newall)


You should have no trouble upgrading your motherboard.  All you have to do 
is remove all the cards, take out the old board, put the new board in, and 
re-insert all the cards.  Now, a couple of things to look for when buying 
your new motherboard:

1) If possible, try to get a motherboard with an external battery (a little 
1.5" by 0.5" box which connects to the motherboard by means of a jumper-like 
cable) rather than a built-in battery.  When the built-in batteries die, you 
end up having to replace the motherboard.  (That's a pretty expensive 
battery! <grin>)

2) Check the size of your current motherboard.  Chances are that it does 
*not* go underneath the power supply (the power connectors are on the very 
edge).  If that is the case, make sure that your new motherboard is the same 
way.  I've seen '386 and '486 motherboards that extend underneath the power 
supply (these are usually designed for special systems).

3) When I upgraded from an XT to a '286, the strangest thing happened:  The 
slots on the motherboard didn't *quite* line up with the holes in the back 
of my case.  I made do for a while, until I upgraded to a '386.  The moral:  
If nothing else, bring your empty case with you when shopping for a new 
motherboard, to make sure everything lines up.

That's about all I can think of for now.  If you need more info, please 
don't hesitate to ask.

                                                -- Trekkie

--                    
INTERNET:  trekkie@netlink.cts.com (Bryce Newall)
UUCP:   ...!ryptyde!netlink!trekkie
NetLink Online Communications * Public Access in San Diego, CA (619) 453-1115

--------------------------------------------------------------------------

From: Paul S Secinaro <pss1@kepler.unh.edu>
Subject: Re: Upgradable motherboards?


In article <1992Jul29.001119.12966@sura.net> you write:
>Second, I wanted to cull opinions on these "upgradable" motherboards I've
>heard about.  Exactly what do they do?  Some of the appear to simply be
>able to handle higher clock rates than the included chip, so that you
>can swap chips later on.  Others, namely the 486SXs I believe, have
>the OverDrive socket, which I'm not sure what they do - do they supplement
>or supercede the 486SX?  Some have cards you plug in to upgrade performance
>(again either be superceding or supplementing the original chip).

You basically have the right idea of it.  There are a lot of different
upgrade methods used by different manufacturers.  Some have a small
daugthercard that contains the CPU and cache, and you can swap this
with a better CPU if you want.  Others allow you to unplug just the
CPU from the motherboard and plug in a better CPU (I think Zeos does
this).  

The 486 OverDrive socket is a bit different.  It allows you to plug in
a "clock doubler" 486DX2 chip.  This chip then *disables* the 486SX on
the motherboard, and takes over the system.  The chip has a complete
486 architecture, including math coprocessor, internal cache, etc.

Note that you can't just plug a normal 486DX2 into an Overdrive
socket.  You must get the Intel Overdrive chip which is a 486DX2 that
has been slightly modified to work with the 486SX.

Paul

-- 
Niven's Law #14:   There exist minds that think as well as you do, but
                   differently.
Niven's Corollary: The gene-tampered turkey you're talking to isn't
                   necessarily one of them.

-----------------------------------------------------------------------------

Subject: Upgradable motherboards?
From: REE700A@MAINE.maine.edu


   Watch carefully what kind of "upgradable" board you get.  Dell has one
in which the motherboard contains only the BIOS, expansion bus and keyboard
interface.  You upgrade by replacing the CPU card (read an entire motherboard)
which fits in a proprietary slot.  This is an extremely expensive upgrade and
you are forced to upgrade with Dell components (as though they will be the
best in the future).
   The 486SX is a 486 which failed the coprocessor diagnostics.  The 487SX
is a 486DX which has an extra signal to "shut down" the retarded 486 which was
originally on your board.  The Overdrive is a clock doubled 486DX2 with the sam
e "shut down" signal.
   If it is at all feasible, but a good 50MHz 486DX board.  There are good
reasons to make it an EISA, but $$$ is always a limitation.  Then later, upgrad
e it by removing the CPU & placing a pin-compatible DX2 in the socket.


     Stick with AMI bios.   It's the most compatible and I've heard horror
stories about Award and Phoenix Bios...   In order of quality (from what I'm
told) it is Intel > OPTi > C&T.  For EISA, Intel is currently the only choice.

     I have only used motherboards from Micro Connection Technologies (MCT)
which are clones of the various AMI boards (I am told AMI sold them the
designs) and have had very few problems (all of which were readilly resolved
under warrantee) among dozens here in our lab and the hundreds sold by our
reseller (Texgraphics, Old Town, ME (207) 827-4873).
     A friend of mine has a Micronics 486/33EISA with which he is very happy.
I guess I would recommend them.  In addition to the AMI clones, our reseller
carries OPTi 486/33 (AMI BIOS) and recommends them.

     As to EISA - yes, 32 bits, shared IRQ among EISA cards, supports ISA
cards (a plus in any case) and even speeds them up, if the drivers can do
any advanced DMA types.  In fact, an EISA system can double the DMA speed
on an ISA card, provided it supports DMA class C (I think its C).
     In the same manner, EISA is 4X faster than ISA, for EISA cards (2X by
data width and 2X by DMA clock cycle reduction).  Power User?  You should have
seen yesterdays computer chronicles on PBS...  They showed some phenominal
improvements in productivity for mundane tasks based on video speed alone!

    The Orchid Prodesigner IISE is Mighty *%$#@ Fast! ( See my newest post
under comp.sys.ibm.pc.hardware for Specs!).  I would definately recommend
this system (between $5000 and $5500) if the $$$ are available.  This clunky
386/33 (AMI mark V) just isn't the same! (And I don't even own that!)
     Jeff Andle

--------------------------------cut here-----------------------------------




-- 
Bill "Whassamatter?!  Can't you take a joke?!" Barnes   wbarnes@sura.net
Disclaimer:  The author apologizes for any thought-provoking material he may
	     have accidentally included and promises not to do it again.
Datclaimer:  My employers wouldn't WANT to share some of my opinions.