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Can I put an old AT motherboard in ATX case?

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First post, by markot

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Hello,

I got for free an old computer that had a Socket 7 motherboard with some Pentium processor. The AT case which is was built into was in terrible condition, so I removed all parts from the case and disposed the case. The previous owner had drilled holes to the case and used wrong kind of screws so the threads holding expansion cards etc had gone bad.

I'm quite a beginner in this area, but I would like to have the motherboard installed in a new case. Is is possible to install AT motherboards to ATX cases without drilling holes for standoffs at the bottom? Where could I find some detailed information about AT and ATX case measures where I would find all necessary technical data?

If I would like to build a computer case totally from beginning myself, I would at least need this technical data. Then a question about AT and ATX power supplies. Can I put an AT power supply straight to an ATX case or do the dimensions and mounting points differ? I have never assembled any computer from the beginning myself, just replaced hard drives etc.

Reply 2 of 4, by alexanrs

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About the PSU... the biggest issue would be the power switch. On Baby AT PSUs the power runs through the font switch, whereas on ATX ones it does not, and part of the logic is on the motherboard itself. Unless the case was made so the power switch could be replaced by a beefy/bulky AT-style one, you migh be better off doing the following:
1- Put an ATX PSU on the case
2- Get an AT-ATX adapter like this. AFAIK there are better ones that include a -5V regulator in case your ATX PSU doesn't provide it and you happen to use something that requires it (not a lot of stuff do, to be honest)
3- Replace the power switch internally with a latched switch (you can get it from the turbo button on the old AT case... if you did not throw it away already) and connect it to those power wires of the adapter
4- Be happy

Just NEVER connect a small latched switch like that to a true AT PSU. That little switch cannot handle the current and might go as far as cause a fire... on the adapter it is perfectly safe, since it is just a signal line.

Reply 3 of 4, by brostenen

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Yeah... Been up numerous times here. I too have experimented with both AT motherboards in early ATX cases.
And ATX psu's in Baby-AT cases, as one of my Baby-AT boards have both AT and ATX psu connector.
This works all well enough, and for the I/O shield in the back of the case, you could go on ebay or make one out of a sheet of plastic.
Or just cut a hole in a standard shield, for the keyboard connector.

Don't eat stuff off a 15 year old never cleaned cpu cooler.
Those cakes make you sick....

My blog: http://to9xct.blogspot.dk
My YouTube: https://www.youtube.com/user/brostenen

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Reply 4 of 4, by markot

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I found out yesterday that the ATX specification PDF documents contains accurate information about mounting hole locations etc. I found them on a Russian FTP server:

ftp://dnph.phys.msu.ru/pub/datasheets/ATX/

Yhese documents are probably also available in other places.

But about the AT power supplies. I live in Finland and at least one local computer store here (http://www.cruzbroker.fi/) is still selling new AT power supplies, and it surprised me a bit. Didn't know they are still available.

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