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At to ATX psu conversion AGAIN! PLS HLP!

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Apr 2, 2002
Ottawa, Canada
Hate to be a nag, but I am still interested how it is done if anyone knows the answer..

I know this much... It can be done with a simple conversion cable connector adapter thingy bob.

What I don't understand.. is.. where do you pull the 3.3v rail from as a AT psu doesn't have a 3.3v rail only 12 & 5v rails. Keeping in mind that it can be done with a simple connector!?:)

I know what your going to say.... go and buyone for bloody Pete's sake!


I live in Ottawa, Canada, the so called silicon valley of the north, and I walk into a dozen computer/electrical/hardware/plumbing stores AND I MAY AS WELL BE ASKING IF ANYONE KNOWS WHERE I CAN BUY A BOMB!!! Because they look at me in very strange when I ask if they ever herd of a AT to ATX adapter. The guy at the store very nervously tells me no "Never hear of them"
as his finger hammers the the panic button under the counter " Hey Harry we got another freak looking for a AT to ATX adapter" It really sucks. :(

So do I pull the 3.3 rail from the 12v or the 5v rail ? How ?

The how part I can probably figure out because I did it with my 12v fans, got them down to 7v

It's for a mobo that will run with a 150w psu, I have 2 AT200w and 2 AT250w psu's kicking around. I have another amd300 system that has at/atx mobo but the 400amd mobo that I want to setup only has atx connection.

I know I can get it on the internet in the USA and I will do that as a last resort. I'd rather make one myself.


<<<alpha sig test>>>
[email protected] 1.85v mod 8x124Mhz. FBS.
ECS K7S5A. Mobo30-35c/CPU 40-45c.
250w PSU (noname) 3.3&5v=100/[email protected]/15a.
Georce2 MX 400 32meg o/c XP detonator 28.32 drvs.
256 Megs PC133 cas2/SoundBlaster Live Value 1024.
Aopen 8x8x32 CDR/CDWR./Fujitsu 20gig 5500rpm H/D.
Windows 98se/Windows 2000pro.
<<<alpha sig test complete>>>


Jul 17, 2001
Denver, Colorado
buy one of those cables right here:


personally I would not trust it, as it'll have to use some sort of regulation on the 3.3V line to get it so low, and God knows how clean the signal will be once that happens.

Couldn't find any info for making one yourself, but hey that one's only 10 bucks.

:edit: hey, found another for only 5 bucks, look down the page-

:more edit: at second glance I have no idea what those cables are good for. AT mobo connectors on one end, ATX on the other. Don't think they are what you are looking for, but check it out anyway I guess. They are all I could find with a search engine.