[SOLVED] CPU Not Detected: Ryzen 7 2700x / MSI B450 Gaming

[Evil Hubie]

My build has been running smoothly for about three months, but tonight it konked out. No video, and it won't boot properly anymore.

The motherboard shows a "CPU Not Detected" diagnostic. I've checked all the connections, fans and lights all still run, and I've reset the CMOS by shorting it, but no-go. Any ideas for more troubleshooting? Thanks in advance.

Here's the build:
AMD Ryzen 7 2700X 3.7 GHz 8-Core Processor
MSI B450 GAMING PRO CARBON AC ATX AM4 Motherboard
AMD Ryzen 7 2700X 3.7 GHz 8-Core Processor
Deepcool GAMMAXX GTE 56.5 CFM CPU Cooler
MSI B450 GAMING PRO CARBON AC ATX AM4 Motherboard
Crucial Ballistix Sport LT 32 GB (2 x 16 GB) DDR4-3200 Memory
Seagate Barracuda 2 TB 3.5" 7200RPM Internal Hard Drive
Sabrent Rocket 1 TB M.2-2280 NVME Solid State Drive
Sapphire Radeon RX 5700 XT 8 GB PULSE Video Card
Fractal Design Meshify C ATX Mid Tower Case
Corsair RMx (2018) 850 W 80+ Gold Certified Fully Modular ATX Power Supply
Corsair SP120 RGB High Performance w/Controller 52 CFM 120 mm Fan
Crucial Ballistix Sport LT 32 GB (2 x 16 GB) DDR4-3200 Memory
Seagate Barracuda 2 TB 3.5" 7200RPM Internal Hard Drive
Sabrent Rocket 1 TB M.2-2280 NVME Solid State Drive
Sapphire Radeon RX 5700 XT 8 GB PULSE Video Card
Fractal Design Meshify C ATX Mid Tower Case
Corsair RMx (2018) 850 W 80+ Gold Certified Fully Modular ATX Power Supply
Corsair SP120 RGB High Performance w/Controller 52 CFM 120 mm Fan

 

[Lutfij]

As opposed to shorting pins, I prefer to remove the CMOS battery for at least 30 minutes before replacing it. See if that helps. If that doesn't work, try and breadboard the system with bare essentials(one stick of ram, boot drive only and the GPU).

 

[DMAN999]

The first thing I would do is check the 8 pin cable at the PSU and the motherboard and be sure it is properly seated on both.
I had that same issue not long ago when I opened my case to clean out thedust andI bumped the 8 pin CPU cable loose on the PSU end.
I plugged it back in firmly and all was well again.

If that doesn't work I would reset the CMOS like this:

• Unplug the PC (PSU).
• Then press the Power Button for at least 30 seconds.

(the on board ROG LEDs will sometimes flash after 20-30 seconds to show that all power has been drained from the board).

• Use a flat headed screwdriver to short the CLR CMOS (CLRTC) Jumper (Touch both jumper pins with the screwdriver) for at least 15 seconds.
• Plug the PC back in.
• Press the Power Button to turn the PC on.
• Repeatedly tap the DEL key
• A screen should come up telling you to press the F1 key, do that.
• Set the Optimized Default settings and Press OK (this is on the EXIT tab)
• Save and exit the BIOS.
• Tap the DEL key again to enter the BIOS and change any settings you want changed then save and exit again.