Question Pc stopped working out of the blue, turns on and off repeatedly.

Mar 13, 2023
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I have tested components by unplugging everything from the MoBo and then plugging one by one. Currently the issue seems to be the PSU, MoBo or CPU. The pc powers on fine when the CPU is unplugged from the PSU (4pin). Once the CPU is plugged in and i power it on, after a second or 2 it powers down and powers back up.
I thought it might be a short between the MoBo and case so i detached the MoBo and put it on a plastic box so there was no current possible between MoBo and any metal.
Tried connecting the green and black wire on the 24 pin connector with a paperclip and turning the PSU on and that made the fans light up and stay on, so the PSU is at least not totally dead.
Took out the CMOS batt. but no change, tried the reset button, no change, tried grounding the MoBo to something metal with a paperclip, no change.

Plugged a monitor into the motherboard directly to see if the BIOS is opening at all but no response.
Besides the named components only the fans, power button and reset button of the case are connected.

PSU is 500W EVGA
MoBo is GigaByte GA-H1100M-H
CPU is Intel Core i5 7600K - 3.8 GHz
 

Lutfij

Titan
Moderator
Welcome to the forums, newcomer!

Pc stopped working out of the blue, turns on and off repeatedly.
What was the last thing you'd done before the issue cropped up? Might want to elaborate on the stopped working bit as well.

Tried connecting the green and black wire on the 24 pin connector with a paperclip and turning the PSU on and that made the fans light up and stay on, so the PSU is at least not totally dead.
The paper cli method is a failed test, it doesn't tell you how much power the PSU can effectively output towards your entire system. Speaking of PSU, EVGA is the brand of the unit while 500W is the advertised wattage of the unit. What is the model for the unit and how old is it? If you'd like to rule out your PSU being the root of this issue, might want to source(borrow, not buy) a reliably built 450W PSU from a friend or neighbor and then try it out with your CPU, motherboard and ram. If the system powers up, you have your answer.

tried grounding the MoBo to something metal with a paperclip, no change.
You did what...? Mind elaborating on this?

Lastly, please include the specs to your build like so:
CPU:
CPU cooler:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:
Monitor:
 
Mar 13, 2023
3
0
10
Welcome to the forums, newcomer!

Pc stopped working out of the blue, turns on and off repeatedly.
What was the last thing you'd done before the issue cropped up? Might want to elaborate on the stopped working bit as well.

Tried connecting the green and black wire on the 24 pin connector with a paperclip and turning the PSU on and that made the fans light up and stay on, so the PSU is at least not totally dead.
The paper cli method is a failed test, it doesn't tell you how much power the PSU can effectively output towards your entire system. Speaking of PSU, EVGA is the brand of the unit while 500W is the advertised wattage of the unit. What is the model for the unit and how old is it? If you'd like to rule out your PSU being the root of this issue, might want to source(borrow, not buy) a reliably built 450W PSU from a friend or neighbor and then try it out with your CPU, motherboard and ram. If the system powers up, you have your answer.

tried grounding the MoBo to something metal with a paperclip, no change.
You did what...? Mind elaborating on this?

Lastly, please include the specs to your build like so:
CPU:
CPU cooler:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:
Monitor:


1) So the primary issue was that my windows would not boot up, it showed the windows boot repair screen, and so i tried different tricks such as pressing the reset button and such to try to get the pc to boot normally.
At some point i went to the Bios settings, set "Secure Boot" to be enabled and switched the primary boot option from "windows boot manager (SSD with windows installed)" to "(SSD with windows installed)".
After trying to save and restart the pc started booting and powering off like described.

2) The PSU is a EVGA 100-W1-0500
I don't have another PSU available but might buy a new one if that seems to be the issue

3) what i meant by grounding the MoBo is: my friend had a similar issue with his pc and he "reset the CMOS" by taking a paperclip and touching the CMOS battery and anything metal on the MoBo simultaneously. Somehow that worked for him so i thought i would give it a go. This was after trying a lot of other stuff.

4)
CPU: Intel Core i5 7600K - 3.8 GHz
CPU cooler: CoolerMaster (unsure but most likely the Cooler Master Hyper TX3 Evo)
Motherboard: GigaByte GA-H1100M-H
Ram: DDR4 16GB PC 2400 CL15 TEAM (TM) 10J. HG retail
SSD/HDD: Kingston SSDNow V300
GPU: Inno3D iChill GeForce GTX 1070 X3
PSU: EVGA 100-W1-0500
Chassis: Sharkoon VG5-V - Midtowermodel
OS: Windows 10
Monitor: Acer KG241-Q

5)
Disclaimer, i bought this pc as seperate parts about 5-6 years back so parts failing is not that crazy but i just cant figure out which component it is. Also the parts are not great together because this is my first build and i had no idea what i was doing. I barely knew if the parts worked together. I'm thinking of building a new PC with the right knowledge but just don't have the funds for it currently.
 

Lutfij

Titan
Moderator
You should revert to Windows' Boot Manger as the primary boot device/option in BIOS. As for the platform, does the system power up without the discrete GPU in your build? If yes, then you might want to think about borrowing a unit, provided the unit is reliably built and has 550W at the entire system's disposal. If the system powers up without a hitch, then the issue was with your PSU.

Motherboard: GigaByte GA-H1100M-H
Gigabyte don't have an H1100M-H board but they do have an H110M-H. Speaking of board, what BIOS version are you on for your motherboard?

3) what i meant by grounding the MoBo is: my friend had a similar issue with his pc and he "reset the CMOS" by taking a paperclip and touching the CMOS battery and anything metal on the MoBo simultaneously. Somehow that worked for him so i thought i would give it a go. This was after trying a lot of other stuff.
I'd advise you not to do that...
 
Mar 13, 2023
3
0
10
You should revert to Windows' Boot Manger as the primary boot device/option in BIOS. As for the platform, does the system power up without the discrete GPU in your build? If yes, then you might want to think about borrowing a unit, provided the unit is reliably built and has 550W at the entire system's disposal. If the system powers up without a hitch, then the issue was with your PSU.

Motherboard: GigaByte GA-H1100M-H
Gigabyte don't have an H1100M-H board but they do have an H110M-H. Speaking of board, what BIOS version are you on for your motherboard?

3) what i meant by grounding the MoBo is: my friend had a similar issue with his pc and he "reset the CMOS" by taking a paperclip and touching the CMOS battery and anything metal on the MoBo simultaneously. Somehow that worked for him so i thought i would give it a go. This was after trying a lot of other stuff.
I'd advise you not to do that...


1) Yeah, if i'm able to access my BIOS options again i will revert to Windows Boot Manager.

2) As stated in my original post, the only way my system powers on is with just the MoBo and PSU attached. All other components are currently disconnected. As soon as i plug in the 4 pin cable from my PSU into my MoBo for my CPU, the system powers on and shuts off after a second or two. I have not been able to get any monitor to show anything, so accessing the BIOS options is currently impossible.

3) Sorry, i mistyped. It is indeed the H110M-H.
Cannot currently check the BIOS version since i can't access the BIOS.

4) I guess currently my best shot is getting a second 500/550W PSU and testing if it powers up correctly with that. Will look into getting a PSU.

Any other tips that i can try in the meantime are very welcome!