ARRITT@kuhub.cc.ukans.edu (What a waste it is to lose one's mind.) (01/04/90)
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,
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"!)
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?
Thanks for any advice, warnings, etc. that you can give.
I'd be particularly interested in the experiences of anyone who has actually
*done* this, as opposed to speculations that "yes, it ought to work".
___________________________________________________________________
Ray Arritt |
Dept. of Physics and Astronomy | THIS SPACE FOR RENT
Univ. of Kansas |
Lawrence, KS 66045 |
arritt@kuhub.cc.ukans.edu |
arritt@ukanvax.bitnet |
davidsen@sixhub.UUCP (Wm E. Davidsen Jr) (01/04/90)
In article <20726@kuhub.cc.ukans.edu> ARRITT@kuhub.cc.ukans.edu (What a waste it is to lose one's mind.) writes: | 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)? Here's what it takes. Figure 1-2 hours, including getting the system apart, testing, etc. Open the case and remove all of the cards. If you don't know for sure what does what, label them (I suggest masking tape, it comes off). You will probably have to remove some or all of the drives, since they often cover the m.b. Now disconnect the power supply. The m.b. is now held in place by either screws or pop clips. If it's clips you squeeze them one at a time and slide the m.b. up over them. Yes, some will pop back. Clear the room of anyone offended by rough language before removing a "pop-in" m.b. Install the new m.b. with the screws or pop-ins. Connect the power, and install the disk controller and video. Install the floppy disk to the controller. *Check for screws, etc, which have dropped into the box*. One little piece of metal in the wrong place will spoil your day. Now power it up and see if it runs okay as a floppy system. Then install the rest of the boards and the hard disk (if any). Close the box and power up. I suggest that you burn in the system for 100 hours and then run whatever hardware tests you have handy, just for peace of mind. This is what I did when I was building systems for other people. | | 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? For an XT you want a m.b. designed to go in an XT. These are sometimes called "baby AT" boards, but check with the vendor before buying. These things usually line right up and drop in. Check the location of the power connector on the m.b., you may have to hack a cable. Beware boards with builtin serial, etc, since they often need a case which fits them, unless they just connect cables to the m.b.. Be *sure* that any builtin stuff on the m.b., like disk controllers, serial, video, can be disabled! If you want to upgrade your m.b., you will probably want to upgrade you peripherals, too, some time. -- bill davidsen - sysop *IX BBS and Public Access UNIX davidsen@sixhub.uucp ...!uunet!crdgw1!sixhub!davidsen "Getting old is bad, but it beats the hell out of the alternative" -anon
kaleb@mars.jpl.nasa.gov (Kaleb Keithley) (01/05/90)
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! kaleb@mars.jpl.nasa.gov (818)354-8771 Kaleb Keithley
rjd@cs.brown.edu (Rob Demillo) (01/05/90)
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. | ||My question is: what is involved in replacing the motherboard? || |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". Just an additional note here. For those of us who have one of the old IBM "Portable PC's"... The motherboard on the PPC is an XT board. I purchased a 286 'drop in' replacement board for an XT, and I was able to wedge it in just fine. (The PPC has a 200 watt power supply, so they were planning for something, at least.) In addition, the PPCcan have a hard disk...I took a Seagate drive (intended for use as an internal drive), extended the cabling and made an external box for it with a fan. The whole configuration is working just fine... (of course, I'm now in the mood for something bigger and faster, but I don't think I'll try upgrading the mother board a second time...give's me the willies... :) ) - Rob DeMillo | Internet: rjd@brown.cs.edu Brown University | BITnet: DEMILLO%BRNPSG.SPAN@STAR.STANFORD.EDU Planetary Science Group | Reality: 401-273-0804 (home) "I say you *are* the Messiah, Lord! And I ought to know, I've followed a few!"
davidsen@sixhub.UUCP (Wm E. Davidsen Jr) (01/05/90)
In article <24217@brunix.UUCP> rjd@cs.brown.edu (Rob Demillo) writes: | In addition, the PPCcan have a hard disk...I took a Seagate | drive (intended for use as an internal drive), extended the | cabling and made an external box for it with a fan. You can also take out one floppy and put a 1/2 height there. That lets you go up to, say, 300MB is you run ESDI. -- bill davidsen - sysop *IX BBS and Public Access UNIX davidsen@sixhub.uucp ...!uunet!crdgw1!sixhub!davidsen "Getting old is bad, but it beats the hell out of the alternative" -anon
emmo@moncam.co.uk (Dave Emmerson) (01/05/90)
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.
poffen@molehill (Russ Poffenberger) (01/06/90)
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
dkchen@uicsrd.csrd.uiuc.edu (01/06/90)
I am planning to have a mother board upgrade for my Turbo XT, too. All I heard from here are the successful cases, is someone out there has bad luck swapping mother board? Maybe we can learn more from him (her). Also, is it true that all the cards (multi. func,mono/Herculus, HD controler, etc.,) for my Turbo XT can be used on a 386SX mother board without any problem? All comments are appreciated. Dean
bcw@rti.UUCP (Bruce Wright) (01/11/90)
In article <1990Jan5.173839.15620@sj.ate.slb.com>, poffen@molehill (Russ Poffenberger) writes: > > 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 is not quite accurate. 8-bit memory cards will, in general, work just fine on an AT, but can only be used for memory below 1 MB. For older AT's, where there might not be a whole MB on the motherboard, this allows you to use an older memory card on the AT. It doesn't help much with most modern AT-class machines which have a whole MB on the motherboard, because then the 8-bit card can't be mapped onto unused memory (since it can't be mapped onto the unused memory are above 1MB). Of course, memory is cheap enough these days that I can't imagine why anyone would want to save pennies this way -- the performance hit from using 8-bit memory on an AT is substantial, and why are you buying an AT if you aren't interested in performance!? Modern memory is often packaged as SIMMS or SIPS so you might not even be able to salvage the chips from the old memory card -- and even if the AT uses DIPs for the memory, they are probably higher density chips than the old PC memory chips. But they probably aren't worth too much anyway in modern dollars ... Ditto for the disk controllers. Almost all 8-bit disk controllers will work on the AT, but the performance hit is substantial. A disk controller just isn't that expensive, and besides, the XT-class disk controllers can't, in general, support 1.2MB or 1.44 MB floppies. These products don't really work any *slower* on the AT than on the XT, just slower relative to the *rest* of the system than the 16-bit parts. Again, if you aren't interested in performance, why are you buying an AT? > 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. This is a good point, and it might also be worth mentioning that some PC's are not only shorter but also not as deep, so that you may not be able to use full-length cards in some PC's. You must make sure that *both* dimensions of the cards will fit. Also, more rarely, some cards are fairly thick (hard-cards, since they contain a small hard disk, are particular offenders, thougth there are others), and may interfere with the use of neighboring slots. Bruce C. Wright
apollo@bucsb.UUCP (Doug Chan) (01/12/90)
In article <42900059@uicsrd.csrd.uiuc.edu> dkchen@uicsrd.csrd.uiuc.edu.UUCP writes: > I am planning to have a mother board upgrade for my Turbo XT, too. > All I heard from here are the successful cases, is someone out there has > bad luck swapping mother board? Maybe we can learn more from him (her). I upgraded from an 4.77 mhz XT board to a 25 mhz 386 baby AT board (what a jump!) Anyway, I found a few problems: 1) The baby AT sized board won't mount properly into the XT case. On my XT case, it uses 9 stand-off posts (metal ones, not the snap-in plastic things) but only 3 will match the holes on the new board. I wanted to drill new holes in the case and move the posts but I didn't have a drill w/ me at the time... I ended up fixing the board in place w/only the 3 posts and I took the other 6 off of the case, fixed them on to the board and glued the end of the posts to the case! This problem would occur w/older style cases... I believe the newer cases use plastic stand-offs placed on sliding/slotted rails. 2) After the board was installed, I had to place the drive rack back in. Guess what...the baby-AT board is about 3/4" longer than the XT board and that prevented one of the rack's support post/leg from going in. Solution: Bent the rack's leg out of the way and made sure the rack wouldn't touch the top of the motherboard. Again, the newer cases shouldn't have this problem... I checked one and the support leg didn't exist. 3) A minor annoyance but I'll cover it anyway... The 150W power supply seemed a bit marginal. The problem only shows up when doing a cold startup - a lot of times the system won't boot but pushing the reset button will always get it started. Sometimes the HD really has a hard time getting started (this never happened w/the XT board installed so it most likely isn't a 'stiction' problem). This may not be a problem on some systems...if it is, obviously, get a larger power supply. > Also, is it true that all the cards (multi. func,mono/Herculus, > HD controler, etc.,) for my Turbo XT can be used on a 386SX mother > board without any problem? No problems here but watch out for the bus speed (this board has 8/8.3/12.5 mhz settings)... luckily all my old cards can run at 12.5 mhz. For the HD controller, since it is an XT card you'll have to configure your system set-up for 'no drive C: installed' since the controller will handle everything. Also, note that AT cards are taller and you won't be able to re-assemble the case. This may be important if you get a 386 system w/ a 32-bit slot and the only 32-bit memory expansion card happens to be an AT sized card! -Doug apollo@{bucsb/buengc/buengf/raven}.bu.edu