seemingly power supply sequence problem

Hi there.

I have a low end fsp power supply. It has been working fine until I upgraded the mainboard. Fans of cpu cooler and psu rotate and lights on the mainboard are on when I press the power button, but there is no post behavior, the screen keeps black, no video signal input, no buzzer warning.

I thought the Gigabyte A320M was broken, but it worked perfectly with a Delta psu. Then after some trials I found it's the fsp psu doesn't work with most of my mainboards. (Gigabyte A320M/A350M/G41. nforece 650i ultra). All the above boards won't POST if connected to this FSP psu. The only one board it is compatible with is an Asus M4A88TD-M(880G chipset), and it runs with no problem with it, even under heavy loads.

I assume this is because the FSP psu's signal doesn't follow a correct timing sequence when power on, but I know little about this. Is my suspection right? is there a way to fix it?

 

I don't think the Watts is the reason, for my components aren't power demanding. The cpus are 65w at top(1500x with A350m and A320m, E8400 with G41 and 650i ultra, 605e with 880G), and the video cards are 1650/750ti or even integrated. Actually these PCs consume around 150w running benchmarks, a reasonable and efficient point for a 300/350w power supply. And if I use this FSP psu on 880G with a 2.1G 605e, the voltage readings in aida64 are good, the bias are less than 5%. This is why I'm looking for other possible reasons.

 

Yes I have tried all the combination with 5 different mobos and 2 power supplies. All the mobos are good with Delta PSU, but only one Asus works with FSP PSU, and as I've said, this board works fine with it even under (relatively) heavy loads, so I guess nothing is broken, just not compatible problems.