Question System won't turn on once I add the CPU & fan

May 5, 2021
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All of the lights and fans turn on in my system when the CPU is not plugged in. Once I add the CPU and fan it no longer responds to power up.

Initially I did a full system build in the case. Everything is brand new out of the box except for the GPU, which was working fine in a different system just a few days ago.
  1. Phanteks Eclipse P360A
  2. MSI B550 Gaming Edge Wifi flashed to the latest BIOS version 7C91v15
  3. AMD Ryzen 5600x
  4. GameMax RGB 750 PSU
  5. Viper Patriot 2x8 GB DDR4 memory
  6. GPU: Sapphire Radeon R9 270X 2GB GDDR5
  7. T-CREATE PCIe SSD Classic 1TB m.2
The system powered up and all the lights and fans came on before I put in the CPU. Once I put the CPU and fan in, it does not turn on at all. There is no response at all to pushing the power switch. If I take out the CPU and fan the motherboard starts working again.

To narrow things down I changed to a breadboard build with only the motherboard, one stick of memory, the PSU, and a motherboard speaker for debugging. With this minimal build I get the same results. The board turns on fine without the CPU, but when I put the CPU and fan into the motherboard, it does not respond to power up at all anymore. There are no sounds from the speaker and no lights of any kind turn on.

The odd thing is that when the CPU is installed I can push the "Flash BIOS Button" and the red light there will blink, so there is power of some sort getting to the board still, it's just that nothing else works or responds in any way. Is there any further debugging I can do to figure out what's wrong? Is it likely just a defective CPU that I need to return to AMD?

Thank you kindly in advance for any help,

-k
 

Ferimer

Distinguished
All of the lights and fans turn on in my system when the CPU is not plugged in. Once I add the CPU and fan it no longer responds to power up.

Initially I did a full system build in the case. Everything is brand new out of the box except for the GPU, which was working fine in a different system just a few days ago.
  1. Phanteks Eclipse P360A
  2. MSI B550 Gaming Edge Wifi flashed to the latest BIOS version 7C91v15
  3. AMD Ryzen 5600x
  4. GameMax RGB 750 PSU
  5. Viper Patriot 2x8 GB DDR4 memory
  6. GPU: Sapphire Radeon R9 270X 2GB GDDR5
  7. T-CREATE PCIe SSD Classic 1TB m.2
The system powered up and all the lights and fans came on before I put in the CPU. Once I put the CPU and fan in, it does not turn on at all. There is no response at all to pushing the power switch. If I take out the CPU and fan the motherboard starts working again.

To narrow things down I changed to a breadboard build with only the motherboard, one stick of memory, the PSU, and a motherboard speaker for debugging. With this minimal build I get the same results. The board turns on fine without the CPU, but when I put the CPU and fan into the motherboard, it does not respond to power up at all anymore. There are no sounds from the speaker and no lights of any kind turn on.

The odd thing is that when the CPU is installed I can push the "Flash BIOS Button" and the red light there will blink, so there is power of some sort getting to the board still, it's just that nothing else works or responds in any way. Is there any further debugging I can do to figure out what's wrong? Is it likely just a defective CPU that I need to return to AMD?

Thank you kindly in advance for any help,

-k
Reset the BIOS why did you flash it? Its probably not at all compatible. Don't flash anything before hand unless you absolutely needed to. Also don't mess around with changing things before you get a POST. on a basic setup
 
May 5, 2021
3
0
10
Reset the BIOS why did you flash it? Its probably not at all compatible. Don't flash anything before hand unless you absolutely needed to. Also don't mess around with changing things before you get a POST. on a basic setup

Thank you for your help! I thought this motherboard needs the latest BIOS to recognize gen 5 AMD chips. My bad. I have tried resetting by removing the CMOS battery for 5+ minutes. Still no luck after doing that. Unfortunately I can't get a POST in any configuration at all because I can't get the board to turn on once the CPU is installed. It just doesn't respond in any way.
 

Ferimer

Distinguished
Thank you for your help! I thought this motherboard needs the latest BIOS to recognize gen 5 AMD chips. My bad. I have tried resetting by removing the CMOS battery for 5+ minutes. Still no luck after doing that. Unfortunately I can't get a POST in any configuration at all because I can't get the board to turn on once the CPU is installed. It just doesn't respond in any way.
You made sure to remove all sources of power then remove the battery? and discharge any remaining power? Website states that its compatible with Ryzen 5000 series.
 
May 5, 2021
3
0
10
I unplugged the PSU, removed the battery, jumped the power switch pins twice for 10 seconds each, waited five minutes, then restarted. I am getting the same results as before. :-(