Question Random no startup, no power ?

57chevy

Prominent
Jun 29, 2021
4
0
510
So this just started happening last week and today was the 3rd time it happened. Just randomly the next day after a shutdown, my pc wouldn't start up. Nothing at all on power button press. Tried all the known troubleshooting tips and tricks. And the one thing that eventually worked was just unplugging the system, holding down the power button to drain any residual energy, and then trying to start up 30 minutes later. It's not a CMOS clear though. I noticed my wireless earbuds charging light would turn on for a second or two after the unplug procedure. I'd plug the the PSU back in and flip the power switch on the PSU and the earbuds would light up then turn off. So it seems like power was going through the mobo and feeding the USB ports for a split second. After doing the unplug procedure a couple of times, the system starts up no problems at all. Is this signs of a motherboard failure in the near future? I haven't gotten any BSOD's in months so I don't know if this is a possible hardware failure. The only thing that I noticed was the clock's time was off once in a while. Gonna build a new system in the future but just need this bad boy to last a few more months to get the money. Any help or insight would be greatly appreciated. Thanks in advance.

i7 7700
ASRock H270M Pro4 Micro ATX mobo (BIOS Fully updated)
Windows 10 64 bit
Seasonic 550 Watt 80+ Bronze
G.SKILL Ripjaws V Series 16GB (2 x 8GB) 288-Pin DDR4 SDRAM DDR4 2400
MSI Radeon RX 570 8GB GDDR5 Armor OC

Troubleshooting tips already performed:
Plugged directly into wall outlet
Clear CMOS (also replaced CMOS battery)
PSU swap (also did the paperclip trick to both PSU's to make sure they worked)
Pulled a RAM stick
Disconnect GPU

Possible variable: My case is about 2 feet above a window air conditioner. The previous owners decided an air conditioner near the floor was pure genius. Anyway, the air blows under the case and into the room. Could there be a moisture issue?
 

57chevy

Prominent
Jun 29, 2021
4
0
510
Other than your mouse and keyboard do you have anything else plugged in to usb slots?

I got a set of wireless earbuds that I charge through a USB port. I've tried starting up with the system stripped down to just CPU and single RAM in different slots and got nothing.

Honestly it's weird how random the startup can happen. 1st time I got it to startup again, the system was stripped to CPU and fan, case fans, and 2 RAM sticks. No GPU, USB's, or monitors. 2nd time everything was plugged in except the PCIe power to the GPU. 3rd time everything was plugged in as normal. The only common thing was the PSU was either unplugged or powered off for a bit of time. But I a different PSU and had the same no startup/no power outcome. A new CMOS battery and cleared CMOS didn't work either.
 

57chevy

Prominent
Jun 29, 2021
4
0
510
The only thing I can suggest is to pull your 24 pin power cable and all other power related cables and reseat them. You can also check inside your case to make sure there is nothing grounding out, or bare metal touching your motherboard.
I've reseated the cables multiple times but never thought to look for the motherboard possibly grounding. I'll give it a good once over. Thanks for the help.