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Is it possible to use ATX PSU for older PC?

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vol.litwr

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I have MB with 386DX 25MHz CPU and 16 MB RAM. I have also two ATX PSU with 20 and 24 pins. Is there a way to use any of this PSU with the mentioned MB? A lot of thanks in advance for any help.
 
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yes they make adapters to use ATX power supplies on AT boards, you can find them all over ebay

how well they work I don't know as I have never used them
 
Thanks! Sorry for the question. I saw the BIG PROBLEM in providing 3.3V minimum loading. I hope I can find a proper adaptor...
 
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Even Radio Schack still stocked them a few months ago. Probably not anymore, but that's indicative of a problem with Radio Schack, not the availability of AT power supplies.

I was buying them regularly for industrial purposes.
 
Biggest problem with the ATX->AT converters is that ATX has no -5v line, while AT does.
You can usually get away with this, because the -5v is not used by floppy drives, harddrives, and the motherboard itself. It is however exposed on the ISA bus, and there are some devices that use it.
 
Scali said:
Biggest problem with the ATX->AT converters is that ATX has no -5v line, while AT does.
You can usually get away with this, because the -5v is not used by floppy drives, harddrives, and the motherboard itself. It is however exposed on the ISA bus, and there are some devices that use it.
Click to expand...

I had this problem on my IBM 5150 board, it would cause a tape relay error on POST.
 
Scali said:
Biggest problem with the ATX->AT converters is that ATX has no -5v line, while AT does.
You can usually get away with this, because the -5v is not used by floppy drives, harddrives, and the motherboard itself. It is however exposed on the ISA bus, and there are some devices that use it.
Click to expand...

Thanks again. :) I have Trident VGA, IDE/FDD and i/o-port ISA cards. I hope they don't use -5V line.
 
Scali said:
Biggest problem with the ATX->AT converters is that ATX has no -5v line, while AT does.
You can usually get away with this, because the -5v is not used by floppy drives, harddrives, and the motherboard itself. It is however exposed on the ISA bus, and there are some devices that use it.
Click to expand...

For the rare device (a few years ago, devices were itemized on the forum), you can always employ a small dc-dc converter, or a regulator on the -12 line. Mostly, the -12 was used as the substrate bias on some DRAM (e.g. 4115) chips, so you're talking about a milliamp or less of current draw.
 
I've found that the old, original IBM PC, and PC-XT power supplies are much more reliable (and have much longer service lives) than clone supplies and the newer ATX type power supplies. I used them for years as standalone power supplies to run my floppy drive testers and 5.25" floppies and hard drives during testing and servicing.

The only reason I am not using them as part of my test rigs right now, is because I had customer that came along and need replacement power supplies for either PC or PC-XT type cases, and I didn't have anything else sitting around that was working.

The original PC power supplies were only rated 63W, and not rated to run the 5.25" hard drives of the time, but I used them when testing hard drives anyway, and they never failed to run properly working 5.35" hard drives.
 
When my daily driver was a PC/XT, it never even occurred to me that the power supply might not be up to the task when I installed a hard drive. It ran for years like that.
 
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