I have found motherboard Fastfame Computer 3VAAV which I cann't turn on by shorting ATX switch pins on front panel out.
I have found solution for "emergency" turn on by pulling out BIOS clear settings jumper. When I do that system starts and I put jumper to original position.
Of course, this involves restoring factory settings. I remember those problems was often in that era and if I'm right that was south bridge failure and no option to make a short circuit to bypass it and turn on and off by other method. Please correct me if I'm in wrong. Apart from that, the board works properly.

EDIT. Diagnose was to quickly. I can't pass post and boot to FDD/CD/HDD 🙁