Question Computer will POST once, then won't unless i reset CMOS

Sep 20, 2020
3
0
10
0
Hi guys, first i'll leave the specs.

EVGA 600W 80+ Bronze
Asus Prime B450
Ryzen 5 3500
HyperX 2x8Gb 2666Mhz
Corsair MP 510
Be Quiet! Pure Rock 2 Black
RTX 2070 Super

----------------

So today was cleaning saturday, and since during the week i've purchased a new CPU cooler i took the oportunity to install everything.

I pulled everything from the case. Cleaned the dust with some air as usual, dissasembled the PSU to take out the hair and lint build up, installed the new CPU Cooler and assembled everything back together. I've done this before with multiple builds, no big deal.

Now, after i try to start my system again. It won't post/boot. The fans will be at 100%, keyboard and mouse will light up but it will stay black.

I proceed to do a CMOS reset, pulled the RAMS and the BIOS battery, waited a couple of minutes and assemble it back. Now i do have POST but with a warning about a bad start, i will add screenshot later. So i press F1, go into the BIOS and i can see my RAMS, the CPU, it seems like everything is working fine.

Save & Exit.

After reboot, it won't POST back, black screen and everything seems to be turned on, Motherboard lights up, all fans at 100%(They usually quiet down after a few seconds but not now). But it doesn't do anything else. I've tried the same thing a couple of times and the behaviour is the same, will post ONCE after i do a CMOS reset but won't after that.

Any clues? Never seen this behaviour before.

---------------

UPDATE 1: I've repeated the process i detailed earlier and for some weird reason, i was able to POST and open the SO. Tried a few times but Restart/Shutdown cycle got really slow after the second try. It used to take seconds now it takes quite a long time. Very strange.

The system feels a bit off, could the motherboard be the culprit?

View: https://imgur.com/PJSBkWu


View: https://imgur.com/GJeUIBF


View: https://imgur.com/019qoZs


---------------------------------


UPDATE 2: I'm having some random key presses on the keyboard when im trying to type. Discovered by accident while changing the USB Port that as soon as i touch the case, the pressing stops. I've replicated this several times now.

Slow boot cycle issue continues even when grounding the case with my foot. Actually painfully slow (almost 120 seconds) for being an NVME.

Could this be summed up as a PSU issue? Grounding issue?
 
Last edited:

white.a.drew

Reputable
Oct 14, 2017
1,245
91
5,590
66
Hi guys, first i'll leave the specs.

EVGA 600W 80+ Bronze
Asus Prime B450
Ryzen 5 3500
HyperX 2x8Gb 2666Mhz
Corsair MP 510
Be Quiet! Pure Rock 2 Black
RTX 2070 Super

----------------

So today was cleaning saturday, and since during the week i've purchased a new CPU cooler i took the oportunity to install everything.

I pulled everything from the case. Cleaned the dust with some air as usual, dissasembled the PSU to take out the hair and lint build up, installed the new CPU Cooler and assembled everything back together. I've done this before with multiple builds, no big deal.

Now, after i try to start my system again. It won't post/boot. The fans will be at 100%, keyboard and mouse will light up but it will stay black.

I proceed to do a CMOS reset, pulled the RAMS and the BIOS battery, waited a couple of minutes and assemble it back. Now i do have POST but with a warning about a bad start, i will add screenshot later. So i press F1, go into the BIOS and i can see my RAMS, the CPU, it seems like everything is working fine.

Save & Exit.

After reboot, it won't POST back, black screen and everything seems to be turned on, Motherboard lights up, all fans at 100%(They usually quiet down after a few seconds but not now). But it doesn't do anything else. I've tried the same thing a couple of times and the behaviour is the same, will post ONCE after i do a CMOS reset but won't after that.

Any clues? Never seen this behaviour before.

---------------

UPDATE 1: I've repeated the process i detailed earlier and for some weird reason, i was able to POST and open the SO. Tried a few times but Restart/Shutdown cycle got really slow after the second try. It used to take seconds now it takes quite a long time. Very strange.

The system feels a bit off, could the motherboard be the culprit?

View: https://imgur.com/PJSBkWu


View: https://imgur.com/GJeUIBF


View: https://imgur.com/019qoZs


---------------------------------


UPDATE 2: I'm having some random key presses on the keyboard when im trying to type. Discovered by accident while changing the USB Port that as soon as i touch the case, the pressing stops. I've replicated this several times now.

Slow boot cycle issue continues even when grounding the case with my foot. Actually painfully slow (almost 120 seconds) for being an NVME.

Could this be summed up as a PSU issue? Grounding issue?
Is your bios up to date?
 

Paperdoc

Glorious
Ambassador
The fact that your system seems to be getting random input signals (some as keypresses) that can be eliminated merely by touching the case suggests there is a grounding problem.

How is power supplied to the computer? Does it use a 3-prong cable with a Ground pin? Is it plugged into a wall outlet with those three holes, or into a 2-prong outlet using some adapter? Same questions for any additional peripherals like a printer, scanner, network switch/router, etc. Where the keyboard and mouse plug into the computer (or a USB hub?) are the connections secure and tight?
 
Sep 20, 2020
3
0
10
0
Hello again, i wen't to bed and now i'm troubleshooting again.

UPDATE:

- Last night the PC was working 'fine' other than the random key inputs and the long reboot cycle.

- Today I moved the PC to the table(different wall plug now) and i unplugged every component and started testing one by one. Now I have everything connected and no issues, no random inputs, fast boot cycle. Temps and everything is normal.

I will try now to plug it back to the OG wall plug and see what happens.

The weird thing is, it was working fine yesterday before i took it apart for cleaning.
 

Paperdoc

Glorious
Ambassador
Try this while you are moving everything. The reason for it this. In certain conditions with poor grounding or electrical supply sockets you can get some attached component plugged in "backwards" with resepct to the others and it sets up a small leakage current through the shields of connecting cables. With this sequence you may find such a situation and fix it.

Start with: you know the symptom you are trying to eliminate: slow boot and maybe odd characters "entered". So step by step you check for those and stop if it happens to change something.
  1. Plug in only the computer and its monitor. Plug in your keyboard and mouse using USB ports on the computer. Turn on and observe. It you have the problem, stop there and disconnect mouse and keyboard, and start up again. Still seem too slow? Disconnect the monitor and start up, noting how long it seems to take before it has finished, even though you can't see the screen. If that fixes the problem, re-connect the monitor BUT plug it into the outlet upside down if you can. See if that solves.
  2. Connect ONE additional component, like a powered USB Hub, or a printer, and boot up. If the problem suddenly shows up, unplug from the wall that new component and try to plug it back in upside down, OR into a different outlet. When this combo is trouble-free, go to the next.
  3. Repeat: add ONE component at a time, and if the problem shows up, change the way it gets it power.
When you get everything connected and working trouble-free, relax and enjoy.
 

ASK THE COMMUNITY

TRENDING THREADS