Question PC refuses to power on for reasons unknown ?

Jun 15, 2021
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PC suddenly refused to power on whole night. Motherboard has light (indicating thr’s power). Upon pressing front panel switch button, nothing happens. Case fan not spinning, no bootup, no POST, no Windows. Screen has nothing.

Specs:
Ryzen 5 2600
Galax RTX2080 base
2x8GB Corsair Vengeance LPX DDR4 3200MHz (DOCP enabled)
1x Toshiba 2TB 2.5” HDD
1x Samsung 970 Evo Plus 500 GB NVMe
NZXT C850 80+ Gold 850W
Asus Prime B450MA mATX.

Everything runs stock, i.e. never OC.

Parts i checked:
  1. Reseat the graphics card
  2. Reseat the RAM
  3. Tried 1 stick of RAM
  4. Tried RAM on all slots.
  5. Checked and reseat NVMe
  6. Checked and replugged HDD
  7. Checked and replugged case power switch cable
  8. Checked and replugged case every front panel cables (HDD LED, Reset Button, Power LED)
  9. Checked case front panels connections (no sign of physical damage detected)
  10. Checked and replugged all PSU cables (24-pin to motherboard, CPU, GPU, HDD)
  11. Case is newly bought, 1.5 weeks old. Cooler Master MB400L mATX.
  12. Dusted GPU PCIe slot
  13. Dusted GPU connector
  14. Dusted both sticks of RAM
  15. Dusted all 4 RAM slots
  16. Tried to power on without GPU inserted into motherboard PCIe, and disconnected 6+8-pin power cables.
Note:
  1. Recently installed a new NZXT C850 PSU 850W 2 days ago.
  2. Recently installed 240 mm AIO cooler for processor.
  3. Did stress test on processor using OCCT, no issue. Processor max temp was around 59-61C.
  4. Did stress test on graphics card using OCCT, no issue. Graphics card max temp was 70C.
  5. PC was running fine for hours each day, for past 2 days.
  6. Did some gaming past 2 days and monitored GPU and CPU temps, all fine. GPU temp at 75C; CPU temp at around 56-58C.
  7. The only part i have not bothered is the processor. I don’t dare to unscrew the cooler and looked into processor as I don’t trust my own hand. Processor requires more delicate handling.
  8. The Samsung NVMe is the boot drive.
The issue started with old PSU installed. I used to have Corsair CX550M 550W 80+ Bronze for about 2 years plus, and I thought it would be underpowered, hence on last Sunday i swapped to a newly bought NZXT C850 850W 80+ Gold.
Right after swap PSU, PC ran fine for 2 days, until now.

So the issue is not on PSU.

I really don’t know how to explain it when the symptom is this random. I’ve brought my system to 2 local PC technicians and they both were able to plug it in and power up the pc in front of me, showing not a single sign of issue at all. Subsequently, i brought it home and ran it for a day, no issue. However next day in the morning, symptom shows again. My system is embarrassing me.


No help at all. Where else should I check?
 

revodo

Proper
Jun 10, 2021
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It's either a PSU failure (it does happen), or the motherboard is shot. It could technically be a broken power button, but I highly doubt it. It's possible you got a massive power surge that fried your computer.

I really can't see it being anything else.
 
Jun 15, 2021
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It's either a PSU failure (it does happen), or the motherboard is shot. It could technically be a broken power button, but I highly doubt it. It's possible you got a massive power surge that fried your computer.

I really can't see it being anything else.
Hi I'm at work right now, and had my partner just randomly test plugging it in the same power outlet about an hour ago, and the computer turns on.

Yep. It loads into Windows.

So system is definitely not fried at this point of writing.

But I'm saying the problem is still somewhere. As I mentioned, it is very random. It doenst happen everytime but when it does, it does.

It is very random.
 

revodo

Proper
Jun 10, 2021
197
25
120
2
Hi I'm at work right now, and had my partner just randomly test plugging it in the same power outlet about an hour ago, and the computer turns on.

Yep. It loads into Windows.

So system is definitely not fried at this point of writing.

But I'm saying the problem is still somewhere. As I mentioned, it is very random. It doenst happen everytime but when it does, it does.

It is very random.
That's odd. It sounds like the computer is new, but it might be worth replacing the CMOS battery. On rare occasions a dead or faulty battery can cause that issue. Do you have the computer plugged into a UPS by chance? Also a possibility with a bad unit.

Lastly, double check ALL ports on the computer. The smallest foreign metal object touching the connectors can cause a short.
 

Ralston18

Titan
Moderator
What about the power source being used for the computer? Wall outlet, power strip, some surge protector? Ensure that the electrical wiring and any interim devices are not losing connectivity.

A loose connection inside the immediate wall outlet serving the computer could result in intermittent power losses.

Have a knowledgeable electrician check the outlet and its' host circuit.
 

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