Motherboard form factor

[Katydew]

I have a computer that's never worked well that I'm taking apart to learn from and to try to salvage. I've read about AT and ATX motherboard form factors, and I can't figure out what I have in this system. It looks like an AT (DIMMS are parallel to PCI slots), but it has both AT and ATX power supply connectors, and it has something called an ATX Form Card with PS/2 and USB connections. I think it's a cheap board, made by PC Chips, model M726, and it may be the source of the problems that I had.

Can anyone tell me what I have and if I should decide to replace it, what I should get instead. I have a PII 450MHz processor. The case is a small tower style, but I don't know what kind.

Another related question. The DIMMS contacts on the board look like tin, and the memory module (168 pin DIMMS, PC100, 128MB) has gold contacts. I've read that a system may start having problems after 6-12 months with this combination, and that's about the time the problems started. The problems were hang-ups and/or GPFs - several times a day.

Thanks in advance for the help,
Melanie

[Reid]

Here is a link to someM726 User Reviews (http://sysopt.earthweb.com/userreviews/mboards/reviewhtml/PC_Chips_M726.html). It generally appears to be an unstable board, but many described it more colorfully than that.

How much you want to spend and what you want to do with your computer may help determine what would be a good substitute. I'd recommend trying a Google (http://www.google.com) search of motherboard review and get familiar with what is available. I'm sure some people will let you know what they recommend.

I have seen some memory contact corrosion due to dissimilar metals, but don't know if it was causing problems. I was able to remove it with a pencil eraser. Observe static precautions when handling memory.

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reido@my-deja.com

Friends don't let friends install Windows ME

[mjc]

One of the signs of memeory problems are hangups and GPFs, so corrosion is a good possibility. Also there are some boards that are kind of hybrid boards (AT/ATX) (why?) that just seem to confuse matters. So if you plan on using the same case then you need to find out what kind of PS you've got. But in all likelyhood it would probably be easier to get both a new case and MOBO. Maybe everything.

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mjc
Links list:Computer Links (http://www.fortunecity.com/skyscraper/highrise/11/index.htm)

[This message has been edited by mjc (edited 04-28-2001).]

[tjaymadison]

Welcome, Katydew! http://www.PCGuide.com/ubb/biggrin.gif Found this (http://www.motherboards.org/manufacturerd.html?filter=mobos&manufid=89) at Motherboards.org web site. Pictures and all. One kinda funny thing though. They list a M726 and a M726MRT on the first page, but if you click on the M726MRT, the title above the picture just shows M726. Should be easy to pick out your board though. One has two ISA slots and is an AT, the other has one ISA slot and is a baby AT. Each will take a P-III processor, but the BX chipset will prevent you from taking full advantage of the newer hard disks like ATA-66. Integrated sound and audio. I think that ATX form card is to make up for the USB and PS/2 ports not being right on the motherboard, like they are with an ATX board. I'm pretty sure these "hybrid" boards started showing up during the transition to full ATX, so people could keep using their AT cases and power supplies for a while, and upgrade in stages.

If you do want to upgrade beyond what your board/BIOS/chipset combination can handle, you may not be able to use your present case and power supply. The case may not have the correct mounting-hole pattern for an ATX board if you do get one. It also may not have the right cut-out pattern in the back for the onboard USB and PS/2 ports that almost every new board has. The power supply may not provide enough "juice" for the components you want now or in the future. You should be able to use your current floppy, HD, CD/DVD or CDR/CDRW. If you get a mobo with DIMM slots, you should be OK with the RAM you have now. Even if not, RAM prices are headed for the basement. That only leaves the processor. http://www.PCGuide.com/ubb/wink.gif If you want to keep yours, you might as well stay with your present setup. P-II's are most stable with BX chipsets. You might be better off to just get a lower-priced DIMM with tinned contacts. Try BestBuy, CompUSA, etc and you might be able to get 128M for under $40 after rebate(s). They should be able to tell you if it has gold or tin contacts. There is a discussion about gold vs tin contacts right here (http://www.pcguide.com/ref/ram/packGold-c.html) in our very own PC Guide. Good luck, whichever way you decide to go. http://www.PCGuide.com/ubb/wink.gif

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"When I nod my head, hit it with the hammer."
-- (Moe, holding nail, to Curly, holding hammer)

[This message has been edited by tjaymadison (edited 04-28-2001).]

[Katydew]

Thanks for the suggestions. I went to the user review site that you suggested, Reid, and it pretty much confirmed my suspicions. :-)

I have an AT connector on my power supply, so I guess unless I want to replace it too, I'd better stick with AT?

As far as $s, I'd like to go as cheaply as possible. I'd considered buying another used computer with similar components and try to put together one decent PC from the two of them.

After I read about the memory mixed metal contact problem, I did clean the RAM contacts with an eraser, but I didn't notice any improvement afterwards. This computer crashes when you look at it. Goes to show that you usually get what you pay for...

Melanie

[Reid]

The choices for remaining with the AT form are somewhat slim, but the ProComp BS61B (http://www.procomp.com.tw/english/computer/product/mb/sp.asp?type=BS61B), at first glance anyway, looks like it may be a satisfactory replacement for your motherboard. A search on Pricewatch shows that one supplier has it for $35.

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reido@my-deja.com

Friends don't let friends install Windows ME

[Katydew]

OK, I think I have the M726 board. Definitely two ISA slots. But the dimensions of the board are only 9" X 9" (maybe slightly smaller) and the case won't accommodate anything larger.

My purpose in doing this is primarily to learn, but also to salvage something that I can give my cousin to use for word processing and e-mail. I don't want to spend a ton of money, but I also don't want to give her something that's going to cause her problems.

My thoughts now are to replace motherboard, case and power supply - all to ATX form factor. I'd like to put in the PII 450 processor for now, but should maybe consider a board that would also support a PIII. Any thoughts about a Tyan S1857, Slot 1, Socket 370, 440BX AGPset?

I have another computer that I use now so I'm in no hurry to get the other one going. I'll keep reading and asking questions. Thanks also for the link to motherboards.org!

[tjaymadison]

Sounds like a good plan. Don't have any specific model recommendations, but when it comes time to buy, try Price Watch here (http://www.pricewatch.com) or OverStock for surplus and closeouts here (http://www.overstock.com). Good Luck! http://www.PCGuide.com/ubb/smile.gif

ADDED: -- Overstock has lots of mobo's, like this Intel one (http://www.overstock.com/cgi-bin/d2.cgi?PAGE=PROFRAME&PROD_ID=4921&fp=T), but it's factory reconditioned. Still comes w/ warranty though. Plenty of other new models too. http://www.PCGuide.com/ubb/wink.gif
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"When I nod my head, hit it with the hammer."
-- (Moe, holding nail, to Curly, holding hammer)




[This message has been edited by tjaymadison (edited 04-29-2001).]

[Paleo Pete]

Here's the basics on dissimilar metals:

Tin, when in contact with gold and under pressure, forms an oxide on the gold coating that is almost as hard as the gold. It can and will cause problems, lockups and GPF's as mjc suggested are very common results. It can be cleaned off, but not easily, if it gets very thick at all something like scotch brite might even be needed. Most gold plated contacts have a stronger alloy underneath for support and strength, and can withstand some, but not much, abuse.

If this turns out to be the problem, which sounds likely, be careful if you try to save it, damage can be caused trying to clean off the oxide. If the pencil eraser doesn't do the trick, I would not advise trying anything more abrasive. The pencil eraser will eventually rub off the gold, but it will take a while...

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So many idiots, and only six bullets...
Note: Please post your questions on the forums, not in my email.

Computer Information Links (http://www.geocities.com/paleopete/)

[Katydew]

What do you think about using Stabilant 22A on the contacts?

[mjc]

A better solution is of course the use of gold-plated to gold-plated contacts, or even solder-alloy-plated to solder-alloy-plated contacts, either of which may be made more reliable by Stabilant 22/22A/22E.

From the Stabilant application pages. I've used it before when I worked in a recording studio, but forgot all about it, thanks for reminding me.

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mjc
Links list:Computer Links (http://www.fortunecity.com/skyscraper/highrise/11/index.htm)

[This message has been edited by mjc (edited 04-30-2001).]

[uncle_bent]

I would replace this motherboard with an ATX form factor if you have a case that will accomodate it. I can't think of any advantages to sticking with the old AT style motherboard.