MSI B450 Tomahawk Build issue

rod1105

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May 17, 2020
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Hey Guys - I'm in the midst of building a new Ryzen 3600x system with the Tomahawk Max board and I'm trying to get past an issue with the CPU LED red light staying on when powering up. I had the system fully loaded with CPU, RAM, GPU all installed but was unable to get the monitor to display (everything else powered up fine). I noticed the CPU LED red indicator on the motherboard was on so I ran the MSI Flash BIOS button using the latest update. It took some effort to finally get the flashing led indicating the BIOS was being updated but the CPU red light continues to stay on. I removed the RAM, CPU, and GPU to see where the issue might be but after powering up the red CPU light still remains on. I want to be sure that's not due to the fact that the CPU was removed. I'd hate to put it back on with the cooler if the motherboard is the problem and needs to be RMA'd. Thoughts?
 

criccio

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I had to lookup what that light meant.
CPU - indicates CPU is not detected or fail.
Well, I would start by inspecting the pins on the CPU and ensure none are damage/bent. Little hard to tell which one might be the problem (cpu or mobo) without other parts to swap around.
 

rod1105

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I had to lookup what that light meant.


Well, I would start by inspecting the pins on the CPU and ensure none are damage/bent. Little hard to tell which one might be the problem (cpu or mobo) without other parts to swap around.
Thanks - I decided to detach the CPU heatsink and CPU to be sure they looked ok. No bent pins and it seated fine. After reattaching the cpu and cooler I fired it up and still see the CPU LED red light - very frustrating. I would have thought the BIOS update would have gotten past any CPU incompatibilities but now I'm wondering if it is the chip or motherboard causing the problem.
 

criccio

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Yeah, that's exactly what that light means. Either the CPU is dead or the mobo is broken in a way that it's not detecting CPUs.
 

AIM9x

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Sadly, like a previous poster mentioned, it's going to be difficult to figure out if it's the mobo or CPU without having a spare cpu or mobo to swap around. You've already ruled out bent/missing pins and BIOS version concerns, and those are the usual culprits. I assume you've already reset the bios jumper as well. I sense a possible return or RMA in your near future.
 

D-EJ915

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I had a 3600 I bought for a friend die after I shipped the system to her, red CPU ERR LED on the board, got a new CPU and replaced it and then it worked fine. I think you got a dead CPU.
 

learners permit

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Remove the cpu and all other peripherals including ram and gpu. Unplug psu or switch it off and remove the cmos battery. Then bridge jbat1 pins together at lower left of cmos battery to clear cmos for a minute. Replace cmos battery turn power back on and rerun mflash without any other hardware connected to update to latest bios from a properly prepared flash drive mounted in mflash usb port. If this works you should have a functional system when completed.
How to video
 
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rod1105

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I lost power at the house for a couple of days so I was unable to work on the build. I did run the Bios update with all components removed but I'm still getting the red CPU light with nothing installed on the board. I'll see if Micro Center will allow me to swap for another CPU to rule it out as the cause.
 

rod1105

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I just realized that if I power up the motherboard without any components installed, including the CPU, and still get the red CPU light engaged, that would seem to point to a motherboard issue, right? I want to be sure it's not lighting because it's not detecting a CPU.
 

criccio

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I just realized that if I power up the motherboard without any components installed, including the CPU, and still get the red CPU light engaged, that would seem to point to a motherboard issue, right? I want to be sure it's not lighting because it's not detecting a CPU.
Lol no. Remember what the light means.

CPU - indicates CPU is not detected or fail.
 
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rod1105

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A bit off topic but I decided to return the motherboard and try the ROG Crosshair VII, which I'll be picking up later today. I unscrewed the Noctua cooler from the AMD socket on the MSI MB but was surprised to see the cooler was stuck to the chip to the point where it came out with the cooler. It took some effort to separate the CPU from the base of the cooler, which has me worried. I thought the latch would keep the CPU firmly locked down - never seen this before. The CPU pins all look fine but it's just one more thing to factor in should issues continue on the new board.
 

rod1105

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I got the ROG Crosshair MB and have a question on the Bios version. The new board states that it has 2304 Bios but the website is a bit confusing on whether to flash the Bios or not. It states " If your motherboard BIOS version number is greater than the BIOS version listed above (which is 2304), then you will not need to flash your BIOS. However, if your BIOS version is smaller than the version listed above, then you will need to select and download the latest BIOS to update your system". There's no mention as to what happens if they're equal to one another. I suspect I'm ok to skip the update but wanted to throw this out there just in case.
 

DrDoU

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2304 shows support for next gen processors on the website. check it out.
 

rod1105

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Now I'm beginning to freak out. I just replaced both the motherboard and the Ryzen 3600x and I'm still getting the dreaded 8 code along with the steady CPU LED light. Is it possible that the Noctua NH-12S cooler is on too tight (or not tight enough)? I can't imagine why this would happen on two different motherboards and CPU chips. I did update the BIOS version to 3004 via the USB flash so I'm at a total loss here.
 

DrDoU

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last resort pull all components out of the case and start adding one piece at a time. As a matter of fact just hook up the power supply and see what happens.
 

rod1105

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Everything is out. I removed the RAM stick and my M.2 NVme SSD. Just the CPU and cooler is left. I replaced the Noctua with the stock cooler just in case but same CPU error. I feel like there's something so obvious staring at me in the face but I can't see it. I do have a spare PSU but the one I have is a brand new EVGA 650w that seems to be working ok. I can swap it out since I'm running out of ideas.
 

rod1105

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Damn - I'm embarrassed to admit this. Criccio, you hit the nail on the head with your PSU comment. I realized that the only other important component that involves the CPU is its power supply. Sure enough I checked the connections under the case and the CPU connector had somehow shifted and was no longer fully plugged. Once that was seated properly CPU LED light stopped and it cycled thru its routine. Unbelievable - didn't need to return the MB or chip after all. :sour:
 
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