Asus Prime H370 not POSTing

[mwijmans85]

dear brilliant minds,

I have a seriously annoying issue, my PC won't boot.

Specs
ASUS Prime H370 plus
Intel core i3 8300 @ 3700 MHz
Hyperx DDR4 2400 16G (QVL ok)
XFX Radeon RX580 GTS
SSD 250G en HDD 2T
Antec Earthwatts Gold Pro 550W

I've built the system and installed everything. It was working fine for a few days untill one day the system went into hybernation. I wanted to reactivate it but it did not respond so I figured, Windows failure. But after a shutdown it wouldn't POST.

The system is receiving power, the fans are working and power LED's are lighting up, but no display whatsoever. When I want to shut down I have to longpress the power button. I went through troubleshooting according to several guides including one from this forum:

checked all cables
disconnected all other hardware in a test setup fashion
tried all memory slots with 1 or 2 DIMM's
measured old PSU (it was good)
replaced PSU with the one listed above anyway
checked for bad pins in the LGA
checked for bad pins in memory slots
checked for bad pins in PCI slots
CMOS clear
CMOS battery extraction
measured power output wall outlet
checked allignement of the stars

I disassembled the system and boxed the mainboard with the RAM and CPU still in placed and went to bed. The next day I went to the store with the components to have them tested but they reported that the system was working fine . I took the stuff home and reinstalled it and indeed, things were working fine. It booted into windows like nothing ever happened.

I used the PC that night and kept an close eye on it's perfomance but things were just fine, no excessive temps on any of the components. When I went to bed and shut down the system, I wanted to see if it would still boot. But no, no POST again, spinning fans, power LED's (mainboard) but no display.

I disassembled the parts again like previous, did some more troubleshooting with the PSU in particular and reinstalled the components the next day and the system booted again. But unfortunately again after a night of use, the next day it would not POST.

It kinda looks like the system needs to 'cool down' or something for at least 24 hours it for it to be able to POST again.

I have never encountered some weird issue like this and I am absolutely clueless on what to do next to fix it.

Can anyone help me out?

 

[romirez]

You have a PCI slot on your mobo and want to troubleshoting?
Try to get *pci post card* and post here post codes of your problems.

 

[mwijmans85]

You have a PCI slot on your mobo and want to troubleshoting?
Try to get *pci post card* and post here post codes of your problems.

I haven't encountered this type of troubleshooting before and have no such card, But it looks like a very unsefull investment. I will see if I can get a hold on one of them and I will post results when I have them.