MSI PRO Z790-A Wifi not working when connecting CPU_PWR1~2 with compatible power supply

[pucho139158502d7]

I have bought an MSI PRO Z790-A Wifi and Im installing it as the manual says with a working power supply P850GM from Gigabyte (which I have already checked that are compatible).
When I'm trying to connect the 24-pin ATX_PWR1 and the 2 8-pin CPU_PWR1~2 the power is not reaching the motherboard (check image "24 and 8 pins connected")and I have checked the power supply separately with other motherboards and it is working correctly, so the power supply is not the issue.

If I connect only the 24-pin on the ATX_PWR1, the motherboard turns on successfully (check image 24 pin only connected). So I'm experiencing an issue regarding the CPU_PWR1~2.

Do you know what can be causing this issue? I don't know if its a defect of the motherboard or what can be done to fix this.

Thanks!

 

[citay]

With only the 24-pin ATX power connected, you will always get the red CPU LED, because then the CPU is not powered, it gets all its power exclusively via CPU_PWR.
So it makes no sense to test like that, you can never get your CPU to work if CPU_PWR doesn't have at least one 8-pin EPS cable connected.

So you're saying, when one or two 8-pin EPS cables are connected to CPU_PWR, the board doesn't respond whatsoever? Then please list all your components in detail, including CPU cooler (i can see it, but i have to check if it's LGA 1700 compatible). You can also remove the CPU and check for bent pins in the socket, this would be a potential explanation for such a behaviour as well.

However, if the pins are all good (none look different from the surrounding ones), then we have to troubleshoot methodically, i'd probably start by testing with a different PSU then. Seems only logical, because you have the famously exploding PSU model from Gigabyte, it has serious design flaws which became obvious in testing. There was a lot of reporting about it, for example,

Unless you have a newer revision where they attempted to fix the worst flaws.

There are also some cases on the forum where users had Z790 boards that were DOA for some reason. But first i would test everything else, because replacing the board would be among the biggest hassles, much more trouble than borrowing a different PSU first for example.

By the way, i hope you use all the mounting screws to secure the board later, they are important for structural support and for grounding the ground layer of the PCB. For testing, it's ok to only use a couple screws temporarily.