is it possible to convert a AT to a ATX

Burning Phoenix · Jul 24, 2003

I have a few old AT psu around and was wondering if i could somehow use them on ATX motherboards. Not for a permanent computer; just an experiment.

Bobby · Jul 24, 2003

There are adapters for the 4pin 12v connector that plugs into the motherboard. I think that's the only difference between AT and ATX power supplies. You just need to make sure you have enough power on all the rails of the power supply.

-Bobby

cack01 · Jul 24, 2003

You could probably rewire it yourself it you found a wiring guide. I think most motherboard manuals have them. If this is for a newer system, I doubt you will have enough power. Also I'm not sure if AT motherboards had a remote wire (green wires 3 & 4 on ATX) so you may just have to connect a loop on the 3 & 4 wires. I bet Hoot could help you a lot on this.

EDIT: here is something off of the Sparkle website. It going to be tuff to get a 3.3V and the 5V you nee.

Question: What is the difference between AT & ATX power supply?

Answer: The differences between AT & ATX power supply are the connector and output voltage. ATX is has a 20-pin connector for mainboard power while AT has two six-pin connectors. ATX has a 3.3V output and +5Vsb, but AT doesn’t.

Question: Does the power supply come with an on/off switch?

Answer: AT power supplies come with an on/off switch. ATX power supplies is not necessary. The on/off switch of ATX units is controlled through the motherboard. However, some models of ATX power supply do come with it.

dudomann · Jul 24, 2003

I was going to ask about this too-

I just picked up an AT case today- i want to use it for just a cheap little server, but i don't want to use the P1 in it- i wan to stick like a p3 in it. The problem that i see isn't the power connector (i'll put a new psu in it) but rather its the way the back of the case is arranged. At the top is the old style- keyboard connector <forgot the name of the damn things> and then my ps2 port, printer port, etc, in the pci slots at the bottom. Realizing that its not going to be pretty, could i not just take a sawzall to the back side of it and open the area up a little bit? Will an mini ATX fit into the screw footprint of the AT case? basically if you have any tips/pointers, i would like to hear them!!!

thx in advance
~Bobb

cack01 · Jul 24, 2003

http://www.a2zpc.co.uk/Form Factors.htm

Many times, computers cases are made to hold different form factors (hole wise) Its very well possible that you could get some holes to mount up, or you can drill your own. The biggest problem, is if you can manipulate the back. From the looks of it you won't be mounting that board vertically anyways. So no need to worry about the holes.

Burning Phoenix · Jul 24, 2003

This is what i'm looking to do with the older AT PSU's. I was at one time starting to buld a diskless SETI cruncher. I already have 2 AMD XP2000's and MB's/ RAM. I have one small HD and one ATX PSU.
My problem starts with this. First i was trying to decide if i should split the output ATX lines into 2 sets with ATX ends for use on the 2 MB's. It's an Antec true power 430W. I don't really want to mess with it though. I also have a DEER 300W ATX i can modify. And then i have various AT PSU's that i had hoped to figure a way to use them on ATX MB's.

BioNiKaL · Jul 25, 2003

i wouldnt convert it though leave it as it is for $30 (aud) you can get a new cheap psu

dudomann · Jul 25, 2003

cack01 said:
http://www.a2zpc.co.uk/Form Factors.htm

Many times, computers cases are made to hold different form factors (hole wise) Its very well possible that you could get some holes to mount up, or you can drill your own. The biggest problem, is if you can manipulate the back. From the looks of it you won't be mounting that board vertically anyways. So no need to worry about the holes.

I'm confused by the last part of the statement- why wouldn't i have to worry about mounting it vertically? Its a stand-up case... even if it weren't you'd still want to attach the mobo to the bottom of the case, no?
~Bobb

cack01 · Jul 25, 2003

dudomann said:
I'm confused by the last part of the statement- why wouldn't i have to worry about mounting it vertically? Its a stand-up case... even if it weren't you'd still want to attach the mobo to the bottom of the case, no?
~Bobb

Sorry I really brain farted on that part. You can mount it vertically.

larrymoencurly · Jul 26, 2003

Most of the AT PSUs I've seen were exactly the same fit as ATX PSUs.

What do you do about the +3.3V that most ATX mobos need and that AT PSUs don't put out? The only practical solution I can think of is to get something like one of those Texas Instruments power modules for free and power it from the +5V or +12V.

star882 · Jul 26, 2003

"What do you do about the +3.3V that most ATX mobos need and that AT PSUs don't put out? The only practical solution I can think of is to get something like one of those Texas Instruments power modules for free and power it from the +5V or +12V."
Now for the 5vsb, use a simple transformer, rectifier, and 7805 regulator PSU(very easy to build).
Then for the PS-On, use some transistors to switch a relay that switches the AC line on the AT PSU.

JKeefe · Jul 26, 2003

All of this sounds like a lot of work and time and possibly extra electrical parts when you can just get a 300W Fortron for $30 inclusing shipping...

Your stability woudn't be in question as much, either.

dudomann · Jul 28, 2003

JKeefe said:
All of this sounds like a lot of work and time and possibly extra electrical parts when you can just get a 300W Fortron for $30 inclusing shipping...

Your stability woudn't be in question as much, either.

Yeah, this was my original intention too ... I like electronics and all, but i'd be afraid of letting the smoke out <I did it to our school Robot once- long story>
~Bobb

TheDogFather · Jul 28, 2003

Whats this about 'Texas Instruments power modules' ? Ive got a server PSU id like to use but it has no 3v line. I started a thread on it, but aint having any luck getting any help

Stedeman · Jul 28, 2003

An adapter is only $6.99 at directron http://store.yahoo.com/directron/atx2at.html

TheDogFather · Jul 28, 2003

That adapter is the wrong way round, atx supply to old motherboard.

larrymoencurly · Jul 29, 2003

The Texas Instruments module I have is the PT8125A, but others are listed here . Notice the "sample" button. To get +3.3V out of an AT PSU, you may want the PT8121 or PT8139. My module is about 1.5" x 4" x .5".

I don't know if they make other versions that take different voltage inputs, i.e., take a PSU with a monster 50A +5V rail and feed it to a module that converts it to +12V.

TheDogFather · Jul 29, 2003

larrymoencurly that site is amazing, ive placed my request. Thanks again.

TDF.

larrymoencurly · Jul 30, 2003

It's wierd how much information most chip companies make available on their websites, not just for their products but also about electronics in general. www.maxim-ic.com , www.linear.com , www.onsemi.com, www.ir.com , www.microchips.com , and www.analog.com are some other company websites with tons of applications notes. On exception is VIA, which won't release information unless you sign a
nondisclosure agreement.

is it possible to convert a AT to a ATX

Burning Phoenix

Member

Bobby

Member

cack01

Member

dudomann

Registered

cack01

Member

Burning Phoenix

Member

BioNiKaL

Registered

dudomann

Registered

cack01

Member

larrymoencurly

Member

star882

Disabled

JKeefe

Member

dudomann

Registered

TheDogFather

Xtreme refugee

Stedeman

The Half Asleep Member

TheDogFather

Xtreme refugee

larrymoencurly

Member

TheDogFather

Xtreme refugee

larrymoencurly

Member

Similar threads