Question Need help with a 2060 super

[Kepler23]

Hello, I have this build

PSU: Corsair CX650M
CPU: 17-4790
MOBO: 18e4 with h81 chipset ( it's from an old HP Elitedesk 800 G1 TWR)
BIOS: 20.02.2020
RAM: DDR3 32GB (4X8)

When I connect my RTX 2060 Super 8GB to the mobo with the PCIE express without the 6+2 pins connected from the PSU it turns on and i get a display saying "please power down and connect all the PCIE cable" fair enough. But when I connect the 6+2 PCIE cable from the PSU it doesn't boot, neither the led on the GPU turns on, nothing at all. I've already tried with another new PSU, it was a 750W PSU, the new one, and even with that the pc doesn't boot, no sign of life inside that case, but it all happens when i connect the 6+2, without the card works fine, obv it wont display nothing apart from the saying that i need to plug the PCIE. I've tried everything, but nothing works, if I plug another GPU, and old GT730 it works fine, but my guess is that it works because that card doens't need the 6+2 cables. I guess the problem is my MOBO at this point, but idk, if y'all got any suggestion please tell me.

 

[Lutfij]

Welcome to the forums, newcomer!

PSU: Corsair CX650M
How old is the PSU in your build?

I've already tried with another new PSU, it was a 750W PSU, the new one, and even with that the pc doesn't boot
750W is the advertised wattage of the unit. What is the make and model of the PSU used to troubleshoot the system?

The motherboard has proprietary connectors, are you using adapters to adapt an aftermarket PSU for your build/motherboard?

 

[Kepler23]

How old is the PSU in your build?

I don't know really, I've bought it used, because i've heard that the GPU needed at minimum 550W, so idk how old the PSU is.

750W is the advertised wattage of the unit. What is the make and model of the PSU used to troubleshoot the system?

The new 750W PSU that I bought for testing if the PSU was the problem is a Mars Gaming MPB750, I know it's not one of the best but I didn't want to spend a lot just for testing the PSU

The motherboard has proprietary connectors, are you using adapters to adapt an aftermarket PSU for your build/motherboard?

Yes indeed, I needed a 24pin to 6 pin, becasue the mother board doesn't have a 24 pin connector, it didn't gave me any problem, it works fine.