ATX shutdown signals

redls1bird · 03-09-2008, 09:07 PM

My power supply (m3atx) has a built in shutdown controller. It controls the shutdown through the atx connector. My motherboard doesnt support this feature. I am wondering what signal is sent and on which pin it is. I am hoping that it fits the same signal that my momentary switch provides and maybe i can just pipe it from my atx connector to the 9 pin connector on my mother board.

Any one have any insight for me?

JimmyFitz · 03-09-2008, 10:14 PM

Most mobo's have the provision for a pushbutton switch to be mounted on the case to act as an on/off switch. You connect the M3-ATX instead of the pushbutton and it send the signal based on the key status.

redls1bird · 03-10-2008, 09:26 AM

I appreciate the response Jimmy. Im not sure i under stand though. I tried removing the 9 pin switch conn. on the motherboard, but it wont respond to the signals the m3 sends through the atx conn. Once i shut down, the only way i can turn it back on is to re-isntall that conector and push the momentary switch. it also wont shut down from the signals sent on the atx.

Im not sure what you mean by "send the signal based on key status".

DarquePervert · 03-10-2008, 09:13 PM

The M3 sends a signal to a two-pin header on the motherboard, the same one that your power switch would normally be connected to.
It doesn't send anything to trigger power on or power off through the 20-pin ATX power connector.

JimmyFitz · 03-10-2008, 11:48 PM

Quote: Originally Posted by redls1bird

I appreciate the response Jimmy. Im not sure i under stand though. I tried removing the 9 pin switch conn. on the motherboard, but it wont respond to the signals the m3 sends through the atx conn. Once i shut down, the only way i can turn it back on is to re-isntall that conector and push the momentary switch. it also wont shut down from the signals sent on the atx.

Im not sure what you mean by "send the signal based on key status".

I was hoping someone else would understand your problem better. The M3 supplies are ment to control your pc startup and shutdown based on your ignition switch status. They do this by simulating the button press on the typical PC case power button. If you connect it by the schematic, you will see that a two pin connector goes to the mobo power button header. You can still use the power button also but it goes to the M3 board first, which then relays the signal to the mobo. Some folks have had issues with the power up/down signal that were resolved by reversing the polarity of the connection. You shouldn't need to do anything to the ATX connector. Search a little, others have had this type of problem before.

redls1bird · 03-11-2008, 08:26 PM

Quote: Originally Posted by DarquePervert

The M3 sends a signal to a two-pin header on the motherboard, the same one that your power switch would normally be connected to.
It doesn't send anything to trigger power on or power off through the 20-pin ATX power connector.

Thanks for that info Darque. I couldnt find anything about what pin would support that on the atx connector and I was just getting really confused. I dont have a 2-pin header for my on off switch, I have a 9 pin. The other pins just run leds for the status lights on the front of the pc. Ill isolate the wires for just the switch and see what I can do.

DarquePervert · 03-12-2008, 04:39 PM

Quote: Originally Posted by redls1bird

Thanks for that info Darque. I couldnt find anything about what pin would support that on the atx connector and I was just getting really confused. I dont have a 2-pin header for my on off switch, I have a 9 pin. The other pins just run leds for the status lights on the front of the pc. Ill isolate the wires for just the switch and see what I can do.

That's usually what you have to do.
If you can look up the motherboard manufacturer's website, you should be able to get a manual. The pin-out information should be in the manual, assuming you can find it.

Another trick....
Connect the motherboard/CPU/RAM/HDD up to a regular ATX PSU.
Use a small flathead screwdriver to short each pair of pins in that bank and note the results.
When the system powers up, note which two you shorted to cause the startup.
Those two pins are your power switch headers.

redls1bird · 03-13-2008, 09:26 PM

Alright. I got it all figured out. My problem stemmed from the on/off cable being wrapped up in the invoice that came in the box. It wasnt connected, and i didnt know i had it. I figured everything i had to work with was already connected. It works great after I isolated the correct pins.

Thanks Darque!