Problem trying to connect "AT" form factory case to a atx motherboard

**spreeway** · June 14th, 2004, 10:52 PM

Hello everyone. I have a problem I was wondering if anyone could help with. I have an old "AT" form factor server case that I want to use for a new server. I have an atx motherboard to install. The problem is that the power button for the case has this 4 prong power connection for its power. I was wondering if anyone new how to hook up the power switch to the new mother board using the atx jumper-type wires.
Thanks

**Kruzin** · June 14th, 2004, 11:04 PM

AT and ATX are not compatible. Not even close.
Backplates are completely different.
Mounting patterns are different.
Power supplies are different (in MAJOR ways).

If you want to run an ATX mobo, you need to get an ATX case and Power Supply.

**Brainchild** · June 14th, 2004, 11:14 PM

well you could get it to work,but the amount of work is beyond the worth.I would prolly pick up a cheap case,and use it

Compgeeks has some cheap models.

**Eladijaz** · June 15th, 2004, 04:45 AM

You would probably be in for quite a bit of modding ...
but to answer your question ...
The power switch for an AT system has 240/120v going through it and is a "hard" switch that allows/stops power to the PSU. (wired to the PSU)
The power switch for an ATX system is an electronic trigger that, when pressed, temporarily shorts power across it, signalling to the board to get moving! (Wired to the motherboard) - you can test this by touching the appropriate pins on an ATX board with screw-driver to start it up.

The other posters are correct tho' ... if you have to buy yourself an ATX power supply you may be spending nearly the amount that it would cost you to buy an ATX case with a power supply in it. Unless you are intending to mod the PSU as well? not sure if this is possible btw ...

Regards,
Eladijaz.

**Eladijaz** · June 15th, 2004, 04:58 AM

to further answer :- you would need to get a different switch ... the nature of the AT switch is that it is push on/push off (toggle). An ATX switch should be a momentary action switch. Your board will hate you if you wire it upto a push on/push off switch, as it will not be able to start until you switch it off again - and the same again for switching the power off - you will need to press the switch twice - also if you leave it toggled on for 4 seconds - an ATX board will shut down... make sense?

**spreeway** · June 15th, 2004, 06:13 PM

Hey thanks guys that helps out. I think i man try to replace the switch with a momentary switch or whatever its called or even just settle with the push twice method. IF I went with the push button twice method, how could i figure out with of the 4 prongs to use with the wire that connects to the mobo?
Thanks.

**spreeway** · June 15th, 2004, 06:14 PM

I ment to say "how could i figure out which of the 4 prongs on the current switch"

**RayH** · June 17th, 2004, 10:46 AM

You can't use the the P/S on the ATX board. If you want to use the case, you'll have to get an ATX supply. But hard core guys hook the RESET as the POWER when using an ATX supply in an AT case. They run w/o a rest button.

I had a buddy with an expensive server case that he didn't want to give up. He had to tap mountings and cut the back to fit the connector panel.

**zepper** · June 17th, 2004, 12:25 PM

Yes, you must get an ATX PSU for an ATX mobo. The mobo power connectors are COMPLETELY DIFFERENT. The power switch is the LEAST of your problems. As others have said, unless that case is unusual in that it was designed to take all types of mobos (many different mobo mounting holes, interchangeable I/O shield with plates for AT and ATX etc., you would have a lot of modding to do. IMO, not worth the effort considering the cost of a case w/ PS these days...
.bh.