The PC does not start, the fans work, it helps to quickly turn on and off through the power supply, how to fix it?

Question

Power Supply

Hello, I recently started having a problem, I don't remember exactly why.
The fact is that the PC does not turn on when turned on, the keyboard of the video card does not light up, but the coolers work at 100%, when turned on they always work at 100% then it subsides, but not in this case, it helped to reset the BIOS battery, and now I use this method of turning on, I turn on the PC, it does not start, I turn it off on the power supply and immediately turn it on and everything works, I have been using it for more than a month, it’s not strange after changing the case, a couple of turns on worked fine, please help. (The speaker is silent, and when I turn on my method 1 signal then there are all the rules, the bios was updated, the mother is gigabyte b350m ver 1.1)

Answer 1

Two main versions: a problem with the motherboard or a problem with the power supply.
The PSU is easier to replace, so it's better to start with it. If you can borrow a BP from a friend for an hour to check, then use this opportunity.
The point is capacitors (but they are on the motherboard and in the PSU). When you turn the PSU off and on quickly, the charge on some of the capacitors is still there, and this helps to start.
Another thing may be an excessive voltage drop on one of the PSU outputs. And in what voltages are on all power lines at the time of launch. The PSU should give a Power Good signal, but if it issues it when it's really "not Good" on one of the lines, then the motherboard starts and freezes. When restarted, the charge stored in the capacitors creates slightly better conditions at the time of launch.

Answer 2

look at how they rebuilt it, since the problem arose after changing the case. or I misunderstood?
I see 2 options so far. or the problem is that the mother is short on the case, or the problem with the PSU itself.
try disabling everything unnecessary (including disks and try to enable