Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!uunet!sjsca4!molehill!poffen
From: poffen@molehill (Russ Poffenberger)
Newsgroups: comp.sys.ibm.pc
Subject: Re: yo mother
Message-ID: <1990Jan5.173839.15620@sj.ate.slb.com>
Date: 5 Jan 90 17:38:39 GMT
References: <20726@kuhub.cc.ukans.edu> <2500@jato.Jpl.Nasa.Gov>
Reply-To: poffen@sj.ate.slb.com (Russ Poffenberger)
Organization: Schlumberger ATE, San Jose, CA
Lines: 60

In article <2500@jato.Jpl.Nasa.Gov> kaleb@mars.UUCP (Kaleb Keithley) writes:
>In article  ARRITT@kuhub.cc.ukans.edu  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.
>>
>Why not spend $350 and get a 386SX?
>
>>My question is: what is involved in replacing the motherboard?  That is,
>>can it be done by someone who is mechanically adept, has some knowledge of
>>electronics, and has done a little bit of fooling around with computer
>>hardware (like installing memory chips or disk drives)?  Or, is it a job
>>best left to a real computer hardware whiz (like most readers of this
>>newsgroup :-)  .... ?  (Maybe the answer is "if you have to ask, then
>>you can't do it"!)
>>
>If you can put in a disk drive, then you can probably handle a motherboard;
>just be carefull, static can destroy CMOS parts on a motherboard faster than
>you can take it out of its static protective bag...
>
>>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?
>>
>What you need is a so called Baby AT motherboard.  This will fit in your XT
>case, but, things like the turbo switch, keylock, speaker, etc (if your XT
>has them) will not "just plug in".  The keylock logic is reversed, i.e. locked
>is unlocked.  I strongly suggest spending $50 and getting a Baby AT case as
>well.  Your XT power supply will fit,  All the switch and light and lock
>wiring will fit, and it is generally a cleaner installation overall.
>
>One additional thought is power supply,  most ATs (especially with lots of ram
>and hard disk) want a minimum of 200 watts.  My XT to AT conversion is doing
>okay with the XT 150 watt supply, but I'm sure lots of people will tell you,
>as they did me, that 150w is on the hairy edge of not working.  Consider 
>spending another $60 for a 200 watt supply.
>Chewey, get us outta here!
>                 

All these point are good, but nobody has mentioned a VERY CRUCIAL point about
replacing an XT m.b with an AT style m.b.

You need to keep in mind what cards are re-useable by the new m.b. Memory cards
ARE NOT re-useable, you need 16bit memory cards. Some 8 bit disk controllers
are also not re-useable, even if they are, the performance will make you want
to get a 16 bit card REAL soon.

This then brings up the other point, some of these new cards you may have to
get (memory or disk controller) are too tall and will not allow you to put the
cover back on if it conforms to a standard XT case dimensions.

I think, with careful shopping, you can find cards that will fit, but you MUST
be sure before buying.

Russ Poffenberger               DOMAIN: poffen@sj.ate.slb.com
Schlumberger Technologies       UUCP:   {uunet,decwrl,amdahl}!sjsca4!poffen
1601 Technology Drive		CIS:	72401,276
San Jose, Ca. 95110
(408)437-5254