Question Pc wont start/has no power

[kaolor0596]

Hello everyone,

I woke up to a completely dead pc the other day. It has no power completely (my ram's LED has no power, fan LEDs no power, motherboard LEDs no power, no power/lights anywhere). I left it in sleep mode the night before which I usually do and have been doing so for the past year or 2. 4 days before my pc died on me, it froze while I was gaming (pretty unusual and rare) and wouldn't restart/shut off unless I completely shut off the PSU. I shut off the psu, unplugged it, plugged it back in and my pc ran fine until it didn't two days ago.



At first I thought it was my PSU so I bought a new one and replaced my old one with it. Still no power or LED lights anywhere. Because my pc still had no power with the new PSU I decided to test/jumpstart my OLD PSU using the paper clip method with the 24 pin motherboard connector. To do this, I plugged into my old PSU only the 24 pin connector and a Pcie connector which I had connected to my fan speed/LED controller. Once I had the paper clip in pins 4 & 7 on the 24 pin connector, my PSU fan and my pc fans along with their respective LED lights came on so I figured my old PSU wasn't the issue. Probably should've tested it out first before rushing into buying a new PSU but whatever.


I quickly returned the new PSU and picked up a new motherboard because thats what I thought was my issue. I swapped in the new motherboard but still had no lights or power anywhere. I made sure my 8 pin cpu connector, 24 pin motherboard connector, and all of the JFP1 cables were plugged in correctly. New motherboard still in pc currently.


Now I'm starting to think it's my case? Could I have possibly have gotten a bad new motherboard? Is there a way to test the motherboard? Or should I buy a new case? Please help and suggest other possibilities! Thank you!

PC spec:
CPU - ryzen 7 3800x
GPU - 6950xt
Ram - 2 sticks of 16gb
Old motherboard - Asus Tuf x570 plus
New motherboard- MSI b550 tomahawk
Old PSU - CORSAIR 850w
New PSU - Corair 1000w (returned already)

 

[Darkbreeze]

Disconnect ALL of the front panel cables from the motherboard and do this, first. That will convict or eliminate the case as being any kind of contributor to the problem. Your case can't cause any kind of power related problem unless there are issues with the front I/O mini board or the power switches, so disconnecting them and jumping the power pins on the motherboard will tell you if that is the case or not.

How to Jump a Motherboard Without a PWR_SW Button

Today's guide shows how to jump a motherboard without connecting the PWR_SW header that goes to the case power button. -

www.gamersnexus.net

If that suggests nothing, then bench it.

How To - Motherboard bench testing

Finding the problem through bench testing If you are here then it’s likely you have encountered a serious hardware issue and have been unable to resolve it using the standard no-POST troubleshooting procedures. If you have not yet attempted to resolve your issues using the no-POST...

forums.tomshardware.com

It's important to eliminate everything that could cause an issue so minimal hardware as outlined in my guide linked to above.

In fact, what are your FULL hardware specs including all model numbers?


As for the PSU, the paper clip test does NOT help to determine if the PSU is bad or not. The ONLY thing that does is tell you if the PSU is COMPLETELY dead. It does not offer any insights as to whether the PSU has any issues other than being TOTALLY dead. PSU could have a variety of ways in which it can fail, including failures of only the 12v rail or one of the 12v rails if it has multiple 12v rails, or the 5v or 3v rails, or fails only under a load, or has a problem with the power ok signal. Or ten other things. Even testing with a multimeter may not tell the whole story unless you are able to put the unit under a load while testing.

What is the model of your original PSU and how long has it been in service?

What was the exact model of the PSU you bought to replace it then returned?

 

[kaolor0596]

Disconnect ALL of the front panel cables from the motherboard and do this, first. That will convict or eliminate the case as being any kind of contributor to the problem. Your case can't cause any kind of power related problem unless there are issues with the front I/O mini board or the power switches, so disconnecting them and jumping the power pins on the motherboard will tell you if that is the case or not.

How to Jump a Motherboard Without a PWR_SW Button

Today's guide shows how to jump a motherboard without connecting the PWR_SW header that goes to the case power button. -

www.gamersnexus.net

If that suggests nothing, then bench it.

How To - Motherboard bench testing

Finding the problem through bench testing If you are here then it’s likely you have encountered a serious hardware issue and have been unable to resolve it using the standard no-POST troubleshooting procedures. If you have not yet attempted to resolve your issues using the no-POST...

forums.tomshardware.com

It's important to eliminate everything that could cause an issue so minimal hardware as outlined in my guide linked to above.

In fact, what are your FULL hardware specs including all model numbers?


As for the PSU, the paper clip test does NOT help to determine if the PSU is bad or not. The ONLY thing that does is tell you if the PSU is COMPLETELY dead. It does not offer any insights as to whether the PSU has any issues other than being TOTALLY dead. PSU could have a variety of ways in which it can fail, including failures of only the 12v rail or one of the 12v rails if it has multiple 12v rails, or the 5v or 3v rails, or fails only under a load, or has a problem with the power ok signal. Or ten other things. Even testing with a multimeter may not tell the whole story unless you are able to put the unit under a load while testing.

What is the model of your original PSU and how long has it been in service?

What was the exact model of the PSU you bought to replace it then returned?

Disconnect ALL of the front panel cables from the motherboard and do this, first. That will convict or eliminate the case as being any kind of contributor to the problem. Your case can't cause any kind of power related problem unless there are issues with the front I/O mini board or the power switches, so disconnecting them and jumping the power pins on the motherboard will tell you if that is the case or not.

How to Jump a Motherboard Without a PWR_SW Button

Today's guide shows how to jump a motherboard without connecting the PWR_SW header that goes to the case power button. -

www.gamersnexus.net

If that suggests nothing, then bench it.

How To - Motherboard bench testing

Finding the problem through bench testing If you are here then it’s likely you have encountered a serious hardware issue and have been unable to resolve it using the standard no-POST troubleshooting procedures. If you have not yet attempted to resolve your issues using the no-POST...

forums.tomshardware.com

It's important to eliminate everything that could cause an issue so minimal hardware as outlined in my guide linked to above.

In fact, what are your FULL hardware specs including all model numbers?


As for the PSU, the paper clip test does NOT help to determine if the PSU is bad or not. The ONLY thing that does is tell you if the PSU is COMPLETELY dead. It does not offer any insights as to whether the PSU has any issues other than being TOTALLY dead. PSU could have a variety of ways in which it can fail, including failures of only the 12v rail or one of the 12v rails if it has multiple 12v rails, or the 5v or 3v rails, or fails only under a load, or has a problem with the power ok signal. Or ten other things. Even testing with a multimeter may not tell the whole story unless you are able to put the unit under a load while testing.

What is the model of your original PSU and how long has it been in service?

What was the exact model of the PSU you bought to replace it then returned?

I did all that you asked in the first paragraph and tried jumping the motherboard but still had no power at all. However I think you're right and it's not the case.

With the second link and a couple of YouTube videos, I took out the motherboard and benched it with the ram still installed, 24 and 8 pin connector connected, along with the CPU and it's corresponding fan. I still wasn't getting any power anywhere even with me trying to jump the board. In a couple of those videos I saw the user move around/remove their ram sticks to test the slots/channels and this gave me the idea to do the same to mine.

I started off removing a ram stick and trying all the other slots with my remaining stick (did it with both). Each time I would reset the PSU and try jumping the board but to no avail. I then put both sticks back in and removed the CPU and the fan. I wasn't expecting any results but with the CPU removed, the motherboard and my ram sticks gained power again after I jumped the board. SO NOW MY ISSUE IS THE CPU?

I forgot i bought a brand new 500W PSU two or three years ago so I decided to use it to do the same bench test as above. Just like my old PSU, this new PSU only gave power once I removed the CPU from the board. Is this normal? (All work done with the new motherboard)

Knowing that my new board could receive power, I decided to test my old one using the same bench method but while also testing both PSUs. Just like above, the board only received power once the CPU was removed. However only the board's LED lights would come on. The LED lights I have on my RAM stays off whereas with the new board, I have power to the board and my RAM sticks. At this point i was thinking something is wrong with my old board and something really wrong with my CPU? Old board, old CPU, old PSU are all approximately a little over a year old. (All bought in June July last year)


Your PSU paragraph had me interested so I tested my old PSU and it's corresponding 24 pin connector(paper clip method) with a multimeter. I had to look up the voltage values online for each pin and some of them were not within their paramter. The multimeter would read 0 on some of the 3s and 5s and one of the 12s the meter read 17. Is this not weird considering the fact that the PSU powered my board without the CPU? I'm going to try this test again tomorrow just to make sure my values of the old PSU are correct. I did this same test with my new PSU and it's 24 pin connector and got correct reading for all pins.

I'm more than likely going to buy a new CPU tomorrow and swap that into all of my old parts to see if maybe the CPU was the heart of all my issues.

Thank you for your help!

 

[Darkbreeze]

If you have seemingly "normal" power response with the CPU removed, then it MUST be either a bad CPU, bent pin(s) on the CPU or is related to the CPU cooler not being EVENLY tight all the way around, with some portion of the retention hardware being tighter or looser than other areas which can "cock" the CPU in the socket and cause it to break the connection to the terminals in the pin bed. I can't think of any other reason why that would happen.

 

[kaolor0596]

My PC is alive again. Thank you for all your help!

I bought the new CPU and installed it into all of my old parts but got no power. I then swapped my old board with the new one and everything came on like clockwork.

So I guess it's safe to assume my issue was with my CPU and motherboard. It's weird for me cause my PC literally died on me in the middle of the night and I did not think that it would be a CPU issue especially because I inspected it and none of the pins were bent or anything. I'm also not an overclocker so none of my previous parts were overclocked. All I ever did in the bios was make sure my ram was running at the correct speed. Somehow in the process of my CPU going bad, I guess my motherboard did as well.

Now I'll have a better understanding of what to do WHEN, not IF, a PC issue happens again. Thank you!

 

[Darkbreeze]

My initial guess would be that maybe there was some kind of electrical event overnight. Power surge, brownout, maybe an issue with the circuit. IDK. Anything is possible. Could even have just been a bad board that took out the CPU. Anyhow, glad you got it going again. Good luck.