power problem

[alphadog]

I use GA-J1900N-D3V in kiosk like system. It requires the MB always stay on when AC power available. Using a power switch is not an option due to a long story circumstances. The MB has option "restore ac power loss", which I have set to "power on". However, there is a situation that MB locks and can't start without pressing power switch. The lock occurs, if AC power is turned on, and immediately turned off, before the beep from PC speaker (around 4 seconds). If AC power switched off after the beep, everything works fine when power restored. Tried with different power supplies, the same. I have checked the output of the PS's with oscioloscope, everything is according to ATX specification v2.2. Tried with F3 (latest) and F2 BIOS, the same.

[MarkJohnson]

I use GA-J1900N-D3V in kiosk like system. It requires the MB always stay on when AC power available. Using a power switch is not an option due to a long story circumstances. The MB has option "restore ac power loss", which I have set to "power on". However, there is a situation that MB locks and can't start without pressing power switch. The lock occurs, if AC power is turned on, and immediately turned off, before the beep from PC speaker (around 4 seconds). If AC power switched off after the beep, everything works fine when power restored. Tried with different power supplies, the same. I have checked the output of the PS's with oscioloscope, everything is according to ATX specification v2.2. Tried with F3 (latest) and F2 BIOS, the same.

It sounds like it is working as intended.  The restore on ac power loss is for when the computer crashes or loses power to cause it to shut off.

It will not turn on your computer just because you plug it in.

There are usually other BIOS option like turn on/turn off at certain times.  Turn on with certain keyboard commands or usb/ps2 commands.  Wake on lan. etc.

by turning it on then off before the beep, means the computer hasn't started up yet and won';t error. 

If you wait for after the beep, it seems to think it is an error and auto-boots as it's suppose to.

You may want to install a hidden switch somewhere so you can turn it on/off manually like you're suppose to.  This turning off/on power all of the time is not good for your system at all.

or maybe I'm just not understanding your issue as you didn't explain your issue fully.  If you want more detailed help, you may want to provide us with as many details as possible.