Z390-E sometimes my pc won't power on

[eggmop]

Hey!
I'm having an issue with my PC, and its really head-scratching to figure out what is causing my issue.
A few time a week, my computer doesn't start after pressing the PC case power button.
It's not major, but it is concerning and I am trying to figure out what the issue is.

Specifications:
Motherboard: ROG Strix Z390-E, BIOS (v.1502)
PSU: Corsair HX750, Model number: SKU CP-9020137 , not sure of the amps.
GPU: Gigabyte GeForce RTX 2080 super gaming OC white 8G
CPU: i7-9700K 3.60GHz, unparked, overclocked to 4.9GHz
RAM: Vengeance LPX C16 2x8GB DDR4 2666MHz black, no overclock
Vengeance LPX C16 2x8GB DDR4 2666MHz white, no overclock
Operating System: Windows 10 Version 1909
M.2: Intel 660p
Monitor: AGON AOC AG352UCG6 3440x1440 @ 120Hz with G-sync enabled
Case: Corsair Carbide Series 400C (around 2017 model)

What happens:
The power cable is plugged in and the PSU switch is in the ON position.
Motherboard RGB lights are ON, indicating it has power.
I press the PC case power button once. The PC case button does not light up.
There is a sudden click from inside the PC. No fans spin. No additional motherboard q-led light indicators go on.
If I press the power button again nothing happens. The motherboard RBG lighting is still on.

Note:
Sometimes when I turn my PC on and don't encounter the issue, the power button light goes on, PC fans start spinning.
Then the PC turns itself off for a second (start button light goes off), and then back on again and boots correctly with no issue.

Eight months ago I upgraded my PSU from an older HX750 model to their new model (silver and black SKU CP-9020137) due to fan noise issues. Until now its been good. The issue also happened when I had the motherboard version 1401 for the Z390-E.

Things I have tried far:

• Updated bios to v1502 for the Z390-E. As well as the chipset drivers.
• Disabled fast boot.
• Reset bios settings.
• Changing the power cable. Sometimes this allowed my PC to start, but the issue still arose on the different cable.
• Using a different electrical outlet (my PC power cable is plugged directly into an electrical outlet). Sometimes this allowed my PC to start, but the issue still arose on a different socket.
• I've checked to see if the PC case button is the issue by using the reset power button as the power button. Same issue persists.
• On the Z390-E motherboard there is a MemOK!_II switch, I have turned this OFF. No change.
• I have checked all cable connections to the motherboard by re-plugging everything. It all seems in order.
• Reset Cmos by removing the motherboards button battery whilst the PC is off for 20 seconds.

Things I'm considering to still do:

• Change HX750 Rail settings switch? It's currently on factor default.
• Buy new IO power cables
• Find if there is a way too turn the pc on without the case power buttons

The one brute force thing that seems to work when I encounter this issue:
Switch psu power button to Off.
Hold down case power button for 10 seconds until there is a click sound.
Instantly switch psu power button to ON whilst still holding down the case power button.
This will sometimes turn on the pc.


Here are some images off my bios settings:






Best,
Eggmop

[Enderwiggin03]

Have you tried a different power supply? Also, you can use a screwdriver to power on the motherboard if you put it between the two power pins (PWRSW PWRBTN# and the GND as shown on page 1-20 in the manual)

[Likashots]

Yeah dude, have you checked to see if your mem test ok is on or off? Your motherboard is just retraining your ram. Sometimes it will restart, sometimes it will just boot up. The motherboard sometimes has to retrain the memory and will restart a few times.

iI you watch inside your case you will see the light orange, then blink red 2x. That means it is training. When it starts orange then gets a solid white light, that means it trained succesfully.

[Enderwiggin03]

Yeah dude, have you checked to see if your mem test ok is on or off? Your motherboard is just retraining your ram. Sometimes it will restart, sometimes it will just boot up. The motherboard sometimes has to retrain the memory and will restart a few times.

iI you watch inside your case you will see the light orange, then blink red 2x. That means it is training. When it starts orange then gets a solid white light, that means it trained succesfully.

His ram's at 2666mhz, I doubt it's a training issue.

[eggmop]

Have you tried a different power supply? Also, you can use a screwdriver to power on the motherboard if you put it between the two power pins (PWRSW PWRBTN# and the GND as shown on page 1-20 in the manual)

I haven't tried a different PSU as I don't have another one. It is the newest Corsair HX750 Model, only around a year old at this point. I did switch out new CPU power cables though. And used different 6-pin connectors for my GPU.

Aweomse thanks, I'll try this next time. I know there is a CPU jumper switch, could I just that on the PWRBTN# and GND pin?

[eggmop]

Yeah dude, have you checked to see if your mem test ok is on or off? Your motherboard is just retraining your ram. Sometimes it will restart, sometimes it will just boot up. The motherboard sometimes has to retrain the memory and will restart a few times.

iI you watch inside your case you will see the light orange, then blink red 2x. That means it is training. When it starts orange then gets a solid white light, that means it trained succesfully.

Heya!
I had MemOK!_II switch on ON before the issue. I have turned this OFF. No change. Should I keep this on?
The issue is that the PC won't turn on. No q-led lights go on, no motherboard lights, no fan spinning, nothing. This only happens sometimes though.

[XYchromosone]

Try switching off the PSU from the wall socket for 30 seconds, then back on again and then try the start power button on the case. My old Maximus XIII Ranger would only start up if I did this. Never found out what caused it because I upgraded to a Maximus X Hero, which worked fine. One day I'll get around to see if I can find out the problem with the old Max VIII, though.

[eggmop]

Try switching off the PSU from the wall socket for 30 seconds, then back on again and then try the start power button on the case. My old Maximus XIII Ranger would only start up if I did this. Never found out what caused it because I upgraded to a Maximus X Hero, which worked fine. One day I'll get around to see if I can find out the problem with the old Max VIII, though.

Will do, cheers for the advice!
Super strange, I take it your PSU was perfectly in order?

[Enderwiggin03]

I haven't tried a different PSU as I don't have another one. It is the newest Corsair HX750 Model, only around a year old at this point. I did switch out new CPU power cables though. And used different 6-pin connectors for my GPU.

Aweomse thanks, I'll try this next time. I know there is a CPU jumper switch, could I just that on the PWRBTN# and GND pin?

No need to use the jumper, you just have to one time make the connection to turn on the PC, leaving that jumper on might cause it to turn off (like holding the power button)