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Question PC refuses to power on for reason unknown

jianh

Junior Member
Jun 15, 2021
4
0
6
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. Cooler Master ML240L.
  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.
  9. The battery CR2032 is weak or maybe dead.
    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?
 
Last edited:

solidsnake1298

Senior member
Aug 7, 2009
205
113
116
Ok. Just wanted to rule out a failing UPS. Could you use the CMOS jumper to clear your BIOS settings? I know you say that you don't OC, but it can't hurt to eliminate variables. You've already tried a lot of the troubleshooting steps for this kind of a problem.
 

jianh

Junior Member
Jun 15, 2021
4
0
6
Ok. Just wanted to rule out a failing UPS. Could you use the CMOS jumper to clear your BIOS settings? I know you say that you don't OC, but it can't hurt to eliminate variables. You've already tried a lot of the troubleshooting steps for this kind of a problem.
Yeah totally agree with you. The list of things I checked are part of eliminating variables too. Now, coming to CMOS jumper to clear BIOS setting, how do I do that? Might be inexperienced in this clearing BIOS procedure so apologies for my stupid question.

Would you mind to share a step by step please?
 

DAPUNISHER

Super Moderator and Elite Member
Moderator
Aug 22, 2001
23,123
4,885
146
Have you changed the battery yet? If so, and the problem persists, you need a new motherboard. Component/s in the power delivery chain are failing, probably a capacitor.
 

Iron Woode

Elite Member
Super Moderator
Oct 10, 1999
29,094
9,539
136
long shot: take a multi-meter and check you wall/outlet voltages. Depending on where you live it should be either 120 or 230.
 

VirtualLarry

No Lifer
Aug 25, 2001
51,935
6,889
126
I don't see where you've tried swapping CPUs. Ryzern-based mobos have some sort of encryption-exchange, when they first POST, where the CPU and the mobo/chipset exchange encryption keys, and sometimes this gets screwed up. I would (AFTER trying everything else, like replacing the CMOS battery, good call DP.), try swapping for a similarly-compatible CPU. If that works, try swapping the original CPU back in. It may work again!

(I had this happen to me, once, or at least, that's what I believe happened.)
 

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