CPU red light after using DDU

[thesilverderp]

I had an annoying issue with my new computer where my new 7900xt caused flickering on the sides of the screen, and I was trying to troubleshoot what might be wrong with it by using an old rtx 3060ti to see if it was actually the cards fault. I checked that the rtx3060ti didnt cause flickering after installing drivers, and I went to use DDU to uninstall all the drivers to put the 7900xt back in, and ended the process by clicking "uninstall and power off" on DDU. When I unplugged the old gpu and plugged in the new one and turned the pc on, all I got was a cpu red light on the motherboard but all the fans spinning to life and the rams RGB lighting up. The computer had been working fine besides the flickering for several weeks, and I had ran it pretty hard to make sure there was no crashing, so I was surprised this happened. I tried plugging back in the rtx, red light. I tried no graphics card, red light. I took out the ram, took out the ssd, still got only the red light. I tried to clear the cmos battery by shorting the two pins as stated in the manual, red light. I took out the cpu, cleaned off the thermal paste and reseated it, and red light. I unplugged every cable and carefully plugged it all back in and still just got the red cpu light. The motherboard didnt even give me the ram light when there was no ram plugged in, just the cpu light. Ive tried everything I can think of short of putting everything in a different motherboard, and still cant fix it. Here are the specs
CPU: AMD Ryzen 7 7800X3D 4.2 GHz 8-Core Processor 
CPU Cooler: Thermalright Peerless Assassin 120 SE 66.17 CFM CPU Cooler
Motherboard: MSI MAG X670E TOMAHAWK WIFI ATX AM5 Motherboard 
Memory: TEAMGROUP T-Force Delta RGB 32 GB (2 x 16 GB) DDR5-6400 CL32 Memory 
Storage: Samsung 990 pro
Video Card: XFX Speedster MERC 310 Radeon RX 7900 XT 20 GB Video Card
Power Supply: EVGA SuperNOVA 850 G+ 850 W 80+ Gold Certified Fully Modular ATX Power Supply

 

Ive heard people suggest actually taking out the cmos battery instead of just shorting pins, but MSI apparently clips in their cmos batteries making them harder to remove without a lot of forcec, so Id rather not do that if I can help it. When I took out the cpu to reseat it, I did take a few pictures of it and the motherboard socket, which are attached.

 

I bought the motherboard refurbished from a reputable motherboard repairer, so the pins that look a bit off should have already been there when it was actually working. As for the cpu, it is also used, so I cant remember if the discoloration was there from the start, or if its indicative of damage that was at some point done to it. 

 

Unfortunately since these were the two parts I got used, I think getting them RMAd might be difficult if there really is a problem. Does anyone have any ideas to fix this, or am I just SOL?

Edited February 17, 2025 by thesilverderp
fixed spelling

[Sawa Takahashi]

As far as I can see the CPU has no external damage on it. A slight discoloration may be normal, especially if it was bought used.

As for the CPU light, please don't throw names at me but did you check if the EPS power cables are correctly inserted into their sockets ? With all the remove/reinsert GPU, it is entirely possible that the cable got slightly loose.

If that doesn't solve the issue, I'd try completely removing the PSU and replugging all cables. If you have another PSU, you can even test with that other PSU while at it.

Keep us informed for more suggestions.

Good luck !

[thesilverderp]

5 hours ago, Sawa Takahashi said:

As far as I can see the CPU has no external damage on it. A slight discoloration may be normal, especially if it was bought used.

I am glad to hear that its likely not damaged, and its some other issue.

5 hours ago, Sawa Takahashi said:

As for the CPU light, please don't throw names at me but did you check if the EPS power cables are correctly inserted into their sockets ? With all the remove/reinsert GPU, it is entirely possible that the cable got slightly loose.

If that doesn't solve the issue, I'd try completely removing the PSU and replugging all cables. If you have another PSU, you can even test with that other PSU while at it.

I must have forgotten to mention it, but one of the first things I did was made sure the cpu cable was plugged all the way into the motherboard. I also did try removing and replugging the cpu and motherboard cable a few days ago, but no luck. I unfortunately dont own a second psu, but I do have to buy a new one eventually since the current one doesnt actually fit into the current case, but thats a separate issue.

 

I have 2 cpu power connector slots on the motherboard. Should I try plugging into the other one or both of them at once? It ran with just one before, but maybe it would help?

[Sawa Takahashi]

49 minutes ago, thesilverderp said:

I unfortunately dont own a second psu, but I do have to buy a new one eventually since the current one doesnt actually fit into the current case, but thats a separate issue.

Well, you got another reason to buy one that fits your case now

50 minutes ago, thesilverderp said:

I have 2 cpu power connector slots on the motherboard. Should I try plugging into the other one or both of them at once? It ran with just one before, but maybe it would help?

There is no harm in plugging two EPS (cpu power) connectors at the same time. I don't remember the specific power that one connector can deliver, but the two are required for a Ryzen 9 CPU. A Ryzen 7 7800x3D uses certainly more power than a ryzen 5 7600, but I don't know at which point the second EPS connector is recommended or required. So, if you go on the safe side, you can plug the two without worries. Just make sure that those are EPS connectors. PCIe connectors look almost the same but have a different pin-out.

Have a nice day !

[thesilverderp]

10 minutes ago, Sawa Takahashi said:

Well, you got another reason to buy one that fits your case now

There is no harm in plugging two EPS (cpu power) connectors at the same time. I don't remember the specific power that one connector can deliver, but the two are required for a Ryzen 9 CPU. A Ryzen 7 7800x3D uses certainly more power than a ryzen 5 7600, but I don't know at which point the second EPS connector is recommended or required. So, if you go on the safe side, you can plug the two without worries. Just make sure that those are EPS connectors. PCIe connectors look almost the same but have a different pin-out.

Have a nice day !

Unfortunately, I don't have another cpu connector, I guess my psu only came with one or I lost the other. I will try plugging the psu into the old pc I have and see if it turns on. I guess if it doesnt, something happened to the psu at some point, but that seems kinda unlikely with it only being a couple of years old. If that doesnt work, is there anything else I should try?

[thesilverderp]

Update, I tried it in my old pc, and unless Ive forgotten how to build pcs completely, which is possible with how annoying this has all been, my psu also isnt working in my old pc. The other pc is giving me a VGA instead of a cpu error, even when the gpu is removed (which I dont think makes much sense because I have integrated graphics in the cpu, so it shouldnt need a gpu). So I guess there is something wrong with the psu itself, or maybe one of the cables? I didnt even think about it as an option tbh, but I guess Ill buy the new psu I was going to get anyways and hope that fixes it. Just to be safe, I tried plugging the psu directly into the wall instead of through my surge protector, so where its connected to probably isnt the issue.

[Sawa Takahashi]

14 hours ago, thesilverderp said:

So I guess there is something wrong with the psu itself, or maybe one of the cables? I didnt even think about it as an option tbh, but I guess Ill buy the new psu I was going to get anyways and hope that fixes it. Just to be safe, I tried plugging the psu directly into the wall instead of through my surge protector, so where its connected to probably isnt the issue.

Plugging into the wall is in case the surge protector has gone bad. It's rare but it happens.

As for why the VGA light acting up, the PSU being probably defective can cause a lot of weird things, including false alarms and no-boot behavior.

I certainly hope that a new PSU will solve all your issues. Even if it is spending money, it is still the least expensive component to replace in a modern PC.

Have a nice day !

[thesilverderp]

4 hours ago, Sawa Takahashi said:

Have a nice day !

Thank you, you too!