PC doesn't turn on

[Letron]

So I built my new computer but it's not turning on, fans spin for half a second and stop, but only the fans that are connected to the fan hub which is connected to the PSU not the motherboard, CPU and GPU fans don't start spinning, nothing on the motherboard seems to activate

 

I tried unplugging and plugging everything, with and without the GPU, I've reconnected the 24 pin, changed RAM position a million times, tried both possitions for the case power switches (the small connectors)

 

The motherboard has LEDs for debugging (EZ Debug LED) but none of them turns on

 

So I've narrowed it down to the motherboard being the problem because apparently PSU works because the fan hub is working for half a second, the case power switches that go the motherboard seem to work because they send the signal to make the fans spin

 

CPU: Intel i5 12600 KF

GPU: AMD Radeon RX 6600 XT

MOBO: MSI Pro B660M-A WiFi DDR4

RAM: Corsair Vengeance LPX 3600 Mhz C18 2x16 GB

PSU: Bitfenix Whisper M 750W

Case: Lian Li Lancool 215

 

 

[CWALD]

I would check the CPU power connector, make sure it is in all the way at both the motherboard and PSU.

 

I've also seen this behavior with Dell PSUs stuck in "test" mode. In this case holding the power button down would result in the fans being stuck at full speed but the rest of the PC doesn't turn on.

 

If you still have a PSU from an old build it might be worth trying it just to see if it turns on. If its not powerful enough for the new system then you can remove the GPU for this test.

[Letron]

Thanks, I'll test it tomorrow morning