Question Board won't turn on when CPU is installed but powers up when CPU is removed.

Jul 4, 2022
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Good day,

I recently purchased the MSI B450 Gaming Pro Carbon AC to pair with my Ryzen 7 3700x as a replacement/upgrade to my old B350 board.

I've assembled it all up and when I pushed the power button it won't turn on. I backtracked and did the basics (ram swapping, disconnect all components, cpu reseating, BIOS flashing, etc) but still won't turn on. Until I removed the 3700x and only the PSU is connected and it finally powers up. I noticed, however, that the EZ debug led for CPU is lit up but I assume its because I removed the 3700X but whenever I place back the CPU to the board it really won't turn on.

The 3700x works fine though when I installed it back on my old B350.

I'd appreciate any help I can get.

List:
msi B450 Gaming Pro Carbon AC
ryzen 7 3700x with wraith prism cooler
Lenovo RTX 2070 Super
Gskill TridentZ 3200 8gbx2
Samsung 970 evo 500gb m.2 nvme
Ramsta m.2 sataIII 1tb
WD blue 2tb sata HDD
 
D

Deleted member 362816

Guest
I bought it used.

He may be right that it needs a newer bios to run that CPU but if it was used unplug the pc pull the cmos battery and let all the settings reset and see if that helps any.

  1. Turn off all peripheral devices connected to the computer.
  2. Disconnect the power cord from the AC power source.
  3. Remove the computer cover.
  4. Find the battery on the board. The battery may be in a horizontal or vertical battery holder, or connected to an onboard header with a wire.
  5. Remove the battery:
    1. If the battery is in a holder, note the orientation of the + and on the battery. Gently pry the battery free from its connector.
    2. If the battery is connected to an onboard header with a wire, disconnect the wire from the onboard header.
  6. Wait 1–5 minutes, then reconnect the battery.
  7. Put the computer cover back on.
  8. Plug the computer and all devices back in.
 
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Colif

Win 11 Master
Moderator
Updating BIOS with Flash BIOS Button
Before updating:
Please download the latest BIOS file that matches your motherboard model from MSI® website and rename the BIOS file to MSI.ROM. And then, save the MSI.ROM file to the root of USB flash drive.
Important Only the FAT32 format USB flash drive supports updating BIOS by Flash BIOS Button.
  1. Connect power supply to CPU_PWR1 and ATX_PWR1. (No other components are necessary but power supply.)
  2. Plug the USB flash drive that contains the MSI.ROM file into the Flash BIOS Button port on rear I/O panel.
  3. Press the Flash BIOS Button to flash BIOS, and the LED next to the button starts flashing.
  4. After the flashing BIOS process is 100% completed, the LED would be off simultaneously

page 45 - https://download.msi.com/archive/mnu_exe/mb/E7B85v1.2.pdf
 
Jul 4, 2022
6
0
10
Updating BIOS with Flash BIOS Button
Before updating:
Please download the latest BIOS file that matches your motherboard model from MSI® website and rename the BIOS file to MSI.ROM. And then, save the MSI.ROM file to the root of USB flash drive.
Important Only the FAT32 format USB flash drive supports updating BIOS by Flash BIOS Button.
  1. Connect power supply to CPU_PWR1 and ATX_PWR1. (No other components are necessary but power supply.)
  2. Plug the USB flash drive that contains the MSI.ROM file into the Flash BIOS Button port on rear I/O panel.
  3. Press the Flash BIOS Button to flash BIOS, and the LED next to the button starts flashing.
  4. After the flashing BIOS process is 100% completed, the LED would be off simultaneously
page 45 - https://download.msi.com/archive/mnu_exe/mb/E7B85v1.2.pdf
Do I rename the zip file or the one inside?
 
Jul 4, 2022
6
0
10
Update.

Still a no-go.

Flashed the bios from the 1st release up to the latest and it still won't power on when the CPU is installed. It does turn on when I flash it because I removed the CPU. This is still weirding me out.

EZ Debug CPU still lights up but I assume its because there's no CPU installed.

I did notice though, there are some instance that the leds on the board flicker once. Like its really attempting to start then shuts off again.

Would this be considered as a dead board already or am I just missing a crucial step?
 
Have you unplugged it?
Hit the power button?
Remove battery?
AND Short CMOS jumper for at least 5 seconds?
This resets bios to defaults and clears all existing memory profiles/ cpu profiles created by the former user.
put the battery back in and plug it in.
Start computer.
Let it run a few minutes before doing anything.
The CPU/BOARD/MEMORY need to go through a "training mode sequence".
This can take a few minutes some times so be patient and do not expect to see anything on screen while this happens.
 
Jul 4, 2022
6
0
10
Have you unplugged it?
Hit the power button?
Remove battery?
AND Short CMOS jumper for at least 5 seconds?
This resets bios to defaults and clears all existing memory profiles/ cpu profiles created by the former user.
put the battery back in and plug it in.
Start computer.
Let it run a few minutes before doing anything.
The CPU/BOARD/MEMORY need to go through a "training mode sequence".
This can take a few minutes some times so be patient and do not expect to see anything on screen while this happens.

I did all if it.

Resetting the bios wasn't necessary because I was reflashing it with a new one to see which one will make it detect the cpu.
The issue is everytime the cpu is installed it wont power up so there isn't any running to begin with. No fan spinning and no lights. It only turns on when there is no CPU in the socket.

It's really frustrating so I gave up on it for now and put back my old b350 and stored the 3700x.
 
D

Deleted member 362816

Guest
Could be the board is DOA. MIght need to RMA it and get a replacement one.

I think he bought it used maybe eBay, If so just return it. I try to avoid buying used motherboards myself if I can not test them prior to buying, To many issues in the past just like this.