Question Upgraded PC, not POSTing

[Remember5n]

Hello everyone!

I've done a small upgrade to my PC. I've changed the case, the power supply and added a new SSD. The PC won't POST though, I get a continuous beep and a red flashing light from the motherboard. But the THING is, I get this behaviour when I switch the PSU on, NOT when I press the power button.

I've never heard of this happening, you usually get motherboard beeps when you press the power button. Does anyone know why this would happen when just switching the power supply on?

 

[Fix_that_Glitch]

What is the motherboard, and how many beeps is it? Just one beep or beeps that you can count?

 

[Remember5n]

It was one short beep repeating ad infinum.
But I fixed it, the motherboard cable wasn't connected properly in the PSU. There were two motherboard slots in the PSU of different sizes and I my line of thinking was the bigger one is for bigger motherboards and the smaller one for smaller motherboards. But apparently I needed both at the same time, the PC boots fine now 😅