Self-Booting motherboard? Why?

[bigbeark]

I have an ECS K8M800 M2 which is a Socket 754. As soon as you turn on the power supply the board boots itself, load the OS. You can't stop the board until you switch off the power.

You can hold down the power button and it turns off, but as soon as you take your finger off the button, it starts up again.

Board is being tested out of the case. No vented caps, but they are all OST.

What is happening here and can it be fixed?

[diif]

Re: Self-Booting motherboard? Why?

Could be a faulty switch or a dodgy power supply.
I've seen both do as you describe.

[Sparkey55]

Re: Self-Booting motherboard? Why?

what does it do if you disconnect the front panel switch from the motherboard?

[stj]

Re: Self-Booting motherboard? Why?

does the psu start on it's own?

[Topcat]

Re: Self-Booting motherboard? Why?

Some boards also have a jumper that will start them automatically.

[bigbeark]

Re: Self-Booting motherboard? Why?

The board is out of the case. It starts without any power switch connected. I have a test switch ( 2 leads and a push button) that I used to try and power the board off. As long as I kept my finger on the test switch, that board stayed off, but when I released the button, the thing booted itself again.

I will try another PSU , but this one works with other boards. There is 1 jumper, JP3, for "BIOS Protect", pins 1-2 enable, pins 2-3 disable. I will experiment with this.
I've had this auto-start behavior on old P3 boards, but they never booted.

The PSU and the board start together, as if I had pushed the power button. I turn the rocker switch on the PSU to "ON" and the board and PSU start together.

[Sparkey55]

Re: Self-Booting motherboard? Why?

Is your "test switch" a momentary ON ( the leads SHORT when pressing the switch button) OR a momentary OFF ( the leads OPEN when pressing the switch button)?

Using the wrong type of switch (Normally Closed,N.C.) will cause this to happen. I suggest checking all your switches with a continuity checker.

Also by default your board will turn off by pressing and holding down the power switch on the motherboard for more than 4 seconds. Soft-Off feature.

[gabiz_ro]

Re: Self-Booting motherboard? Why?

Some boards have in BIOS some settings for power on and for what to do after power loss.

[Sparkey55]

Re: Self-Booting motherboard? Why?

Bump.

[bigbeark]

Re: Self-Booting motherboard? SOLVED

A couple of days ago, I tried removing the test switch and the bios battery from the board, sure enough it booted itself again as soon as I flipped the PSU switch to ON.

Removed the Bios battery and left the board alone. Today tried again. Flipped the PSU switch. Nothing happened. Turned off the PSU switch, Installed a new BIOS battery. Nothing. touched a screwdriver to the power button pins. Starts up, tells me to update the bios settings. I do so and save to BIOS. Hit the Enter key to restart. Board starts up, loads operating system. I select Shutdown from the menu. Machine stays off. PERFECT!

Obviously my dumb mistake. I should have drained the BIOS setting with the jumper. Removing the battery and leaving it to sit drained the previous BIOS settings and got rid of the automatic restart. I was sure the board was set to Stay Off after power outage, but having made this Noob mistake maybe not

[Dan81]

Re: Self-Booting motherboard? SOLVED

A couple of days ago, I tried removing the test switch and the bios battery from the board, sure enough it booted itself again as soon as I flipped the PSU switch to ON.

Removed the Bios battery and left the board alone. Today tried again. Flipped the PSU switch. Nothing happened. Turned off the PSU switch, Installed a new BIOS battery. Nothing. touched a screwdriver to the power button pins. Starts up, tells me to update the bios settings. I do so and save to BIOS. Hit the Enter key to restart. Board starts up, loads operating system. I select Shutdown from the menu. Machine stays off. PERFECT!

Obviously my dumb mistake. I should have drained the BIOS setting with the jumper. Removing the battery and leaving it to sit drained the previous BIOS settings and got rid of the automatic restart. I was sure the board was set to Stay Off after power outage, but having made this Noob mistake maybe not

Power On AC Loss?

I know this feature exists on some motherboards.

[mattch]

Re: Self-Booting motherboard? SOLVED

Power On AC Loss?

I know this feature exists on some motherboards.

Exactly what it is, most mb have a setting to power on after ac power lost. Good for server and headless. I use it in most of my stuff.

Taking the battery out reset the cmos thus the setting is revert back to default, to stay off. You can also open cmos menu and reset all settings back to default.

[R_J]

Re: Self-Booting motherboard? Why?

It is listed in the manual (page 41) In bios under Power Management Setup
PWRON After PWR-Fail (Off)
This item enables your computer to automatically restart or return to its last operating.