Question Pc won’t turn on unless CPU is disconnected.

Feb 18, 2021
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When I turn on my pc it just makes a faint little noise from the psu and cpu area on the motherboard, no lights or signs of turning on. When I turn the pc on without the cpu connected, it turns on as usual, the motherboard is up with its light on cpu in the debug section and all the fans boot up with it.

specs
Amd Ryzen 3500x
Mobo: Msi B550-A Pro
gpu: Sapphire Radeon 5600xt
psu: Corsair 750watt
 
Feb 18, 2021
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When I turn on my pc it just makes a faint little noise from the psu and cpu area on the motherboard, no lights or signs of turning on. When I turn the pc on without the cpu connected, it turns on as usual, the motherboard is up with its light on cpu in the debug section and all the fans boot up with it.

specs
Amd Ryzen 3500x
Mobo: Msi B550-A Pro
gpu: Sapphire Radeon 5600xt
psu: Corsair 750watt
I may add that the motherboard has exerted smoke before, just yesterday when I was trying to see what was wrong with it. The day it all went horrible. I’m a new builder and this was my first build. Even though there was smoke it still works but in the manner I’ve explained in the post.
 
Feb 18, 2021
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Did you use correct standoffs behind the motherboard.
Which plug from the psu EXACTLY did you put in the 8pin port in the top left corner of the motherboard.
Yes, it turns on completely fine but only when the cpu psu connector isn’t in the cpu pins. The cable is directly from the psu and labeled as CPu on the side of the connector. It fits perfectly with the cpu port on the mobo. It just doesn’t turn on when it is connected to the cpu.
 
Feb 18, 2021
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There’s one cpu power connector that comes directly from the psu, like embedded as a cable that can’t be unplugged from the psu. The thing is that I think that it might not be working correctly. The psu does have sockets for another cpu cable however. Would I be able to use that so kept with a cable replacement? Would it be safe?

Some other info: My pc doesn’t turn on whenever I have the cpu power connector plugged into the motherboard’s cpu socket. I’m still trying to determine whether it’s just a bad cable, the motherboard or the cpu.
 
There’s one cpu power connector that comes directly from the psu, like embedded as a cable that can’t be unplugged from the psu. The thing is that I think that it might not be working correctly. The psu does have sockets for another cpu cable however. Would I be able to use that so kept with a cable replacement? Would it be safe?

Some other info: My pc doesn’t turn on whenever I have the cpu power connector plugged into the motherboard’s cpu socket. I’m still trying to determine whether it’s just a bad cable, the motherboard or the cpu.
Doesn't make much sense that one fixed cable would prevent a PC from working.

What PSU?

Why do you think the problem is this connector? Does the PC post when the connector is NOT installed?

What motherboard?
 
Feb 18, 2021
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Doesn't make much sense that one fixed cable would prevent a PC from working.

What PSU?

Why do you think the problem is this connector? Does the PC post when the connector is NOT installed?

What motherboard?
I have a CX750M semi-modular Corsair psu paired with an MSI B550-A Pro

The PC turns on but ONLY when the cpu power connector is disconnected. When it is connected, I hear one faint sound that comes from the motherboard and the psu, mainly around the area you’d plug in the cpu power connector or the cpu itself (i can’t tell), my lights also flick once when I do this. There is no other thing that happens just those sounds and my lights flicking once. With the cpu power connector out, everything starts up, fans and everything.
 

bignastyid

Titan
Moderator
I may add that the motherboard has exerted smoke before, just yesterday when I was trying to see what was wrong with it. The day it all went horrible. I’m a new builder and this was my first build. Even though there was smoke it still works but in the manner I’ve explained in the post.
You released the magic smoke one or more things are damaged, it's not going to work correctly. Showing some signs of life is not the same as working.

Are there any bent or broken pins on the CPU? Did you see the part of the board where the smoke came from? Any visible burn marks?
 
Feb 18, 2021
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You released the magic smoke one or more things are damaged, it's not going to work correctly. Showing some signs of life is not the same as working.

Are there any bent or broken pins on the CPU? Did you see the part of the board where the smoke came from? Any visible burn marks?
There‘s some unexplainable shade on the back of my cpu, the pins are fine, still got luster and are all straight but there are just some parts of it that are a bit darker. I don’t quite remember where the smoke came from but i know it came from around the edges, I quickly turned off the psu the instant I saw smoke so I was a bit dumbfounded by the moment.
 

bignastyid

Titan
Moderator
There‘s some unexplainable shade on the back of my cpu, the pins are fine, still got luster and are all straight but there are just some parts of it that are a bit darker. I don’t quite remember where the smoke came from but i know it came from around the edges, I quickly turned off the psu the instant I saw smoke so I was a bit dumbfounded by the moment.
Can you post a pic of the socket and the pin side of the CPU?
 
Feb 18, 2021
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You released the magic smoke one or more things are damaged, it's not going to work correctly. Showing some signs of life is not the same as working.

Are there any bent or broken pins on the CPU? Did you see the part of the board where the smoke came from? Any visible burn marks?
You released the magic smoke one or more things are damaged, it's not going to work correctly. Showing some signs of life is not the same as working.

Are there any bent or broken pins on the CPU? Did you see the part of the board where the smoke came from? Any visible burn marks?
Here’s a picture
 

bignastyid

Titan
Moderator
Just turn on, i’ve tried getting it to bios as it is a motherboard capable of booting bios without a cpu or gpu but no luck unless I’m doing something wrong.
A cpu and gpu is required to post(post is required to boot). Your board has the ability to update the bios without a cpu, ram or gpu, but that is not the same as posting and entering/seeing the bios.
 
Feb 18, 2021
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A cpu and gpu is required to post(post is required to boot). Your board has the ability to update the bios without a cpu, ram or gpu, but that is not the same as posting and entering/seeing the bios.
Oh ok, my bad. Not too keen when it comes to pc building. I’ve only recently finished this pc as my first.
 
Feb 18, 2021
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No problem, kinda sucks this is your first experience with building. Hopefully you just have to get the motherboard replaced.
I got a new motherboard, everything powers on with everything plugged into the right areas. The only problem is that I dont think it went through the POST thing. The monitor says no signal when everything in the pc is running just fine, fans and everything. Tried multiple things to get the monitor to display but nothing, just the sounds of my pc’s fans.
 
Feb 18, 2021
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Is the monitor input set for the cable input from the gpu?
I think so? The first time I plugged in the cable and turned the pc on it just detected it and displayed right on. It was a DP? Whatever those cables are called. I also used hdmi and dp in all the inputs the gpu had, every port, no luck and no signal on the monitors part ever.
 
Feb 18, 2021
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I think so? The first time I plugged in the cable and turned the pc on it just detected it and displayed right on. It was a DP? Whatever those cables are called. I also used hdmi and dp in all the inputs the gpu had, every port, no luck and no signal on the monitors part ever.
my monitor is an MSI optix g24c, I also need to include that I tried to check to see the inputs for the monitor but none of the buttons on it did anything, just the no signal screen.
 

Karadjgne

Titan
Ambassador
If you have the cable plugged into DisplayPort on the gpu, the monitor needs to be set on DisplayPort too.

I had a similar experience, my DisplayPort monitor failed to activate, even after repeated restarts. I unplugged the cable at the gpu, rebooted, plugged the monitor back in with the pc on then hit shift+winkey+B, which reactivates the gpu drivers.

Monitor popped up.
 

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