Disabling 'Soft Power on' on ATX

Toaster · 06-14-2001, 06:33 AM

Not sure if this is the correct board, but anyhow...

I've got a MicroATX board. After failing miserably to get hold of a DC/DC converter, i've ended up getting myself an inverter.

However, I need to disable the 'ATX soft power on' option on the motherboard so it will power up as soon as the inverter or power supply is turned on (just like an AT board). At the moment it waits until the power button is pressed.

I have searched through the bios options without any luck, and have even tried placing a jumper over the power button connectors on the motherboard. But this just resulted in the computer powering itself back down after a few seconds.

Its got a standard Award Bios. How have the rest of you guys done it?

Technics · 06-14-2001, 06:53 AM

Many mainboards will power up instantly if the power button is shorted. To see if this will work with the board, try plugging in a standard ATX powersupply with the power switched off at the wall, then hold in the soft power button. Switch on the supply at the wall(keep holding in the soft power button the whole time while mdoing this). If the motherboard swithes on and stays on while the power button is depressed then put a jumper across the soft power contacts on the motherboard and it should work. Pheeew, I hope I managed to explain that well enough. If it doesnt work you will have to make a circuit to pull down the signal line of the motherboard for half a second when power is applied. This can be done with a few components. If the fist method does work, let me know and I'll do up a schematic for a circuit to do this. I needed a similar circuit for the power good line for my motherboard

mtmsol · 06-14-2001, 10:14 AM

Try checking in the BIOS - a lot of motherboards have an option to resume after a powerfialure, and if this option is enablede then the PC will boot as soon as you switch on the inverter - this is how I turn my PC on.

Mike.

jshrieve · 06-14-2001, 06:12 PM

My motherboard's BIOS has that powerfail option.

It basically gives me the following choice for what to do after power is restored after a powerfail.

a) stay off
b) always turn on
c) turn on if the computer was on when the power failed.

I use (b), so it always turns on when it gets power.

Toaster · 06-15-2001, 05:17 AM

Thanks guys. I tried to short out the power switch directly on the motherboard again without success. But I managed to find the 'Instant on after power failure' option in the bios. It seems to boot up without any problems now...

Looks like my player is going to be up and running in about a week. I finally got hold of my keypad yesterday and managed to wire it directly to my LCD display. Now all I have to do is wait for the inverter to be delivered and install the whole thing in my car. Looks like im going to have it up and running for my trip to the British F1 Grand Prix this year. Woohoo!

magnetik · 06-17-2001, 11:51 PM

Quote:

Originally posted by mtmsol:
<STRONG>Try checking in the BIOS - a lot of motherboards have an option to resume after a powerfialure, and if this option is enablede then the PC will boot as soon as you switch on the inverter - this is how I turn my PC on.

Mike.</STRONG>

great idea mike, I currently extended the soft power push button, but this would be a nicer solution. My mobo is one of those without the nice ATX soft power options, but im quite sure I saw the power failure options. Me thinks I will have to check!