Build Advice Asus Prime B550M-A No Post

Just bought the parts for my daughter's new PC, and I can't get it to POST. Just put it together on the bench to test, but no go I'm afraid.

Asus Prime B550M-A
16GB Corsair Vengeance RGB Pro (CMW16GX4M2D3600C18)
Ryzen 5600G
Samsung 256GB 980 Pro M.2 NVME
Corsair CX750F RGB PSU

The CPU fan spins up... RAM RGB lights up, but gives 6 bleeps and there's no video output. I've no idea if they are long, or short bleeps, as I've nothing to compare them to (all being same length) but they sound long.

Tried so far:

• Cleared CMOS
• Removed battery and cleared it again
• removed one RAM module and tried in all slots.
• As above with the other module
• Added a GPU
• Tried both HDMI and VGA, on both m/b and gpu (an old, but working GT720 - tested OK on another rig)
  
• Tried M.2 in both slots
• tried without any SSD
• tried with and without k/board and mouse
• tried without any RAM

I do not have another Ryzen CPU, or any other DDR4 to test.

I can find nothing about POST error beeps in the manual, and nothing on the website mentions 6 beeps.

Anyone got any ideas?

Thanks in advance.

 

I had a similar problem when I built my wife's PC. Solved it by ordering an older Ryzen CPU from Amazon, supported by the first BIOS revision, updated to the latest BIOS and all was well. Cleaned up the temporary CPU and sent it back to Amazon for a full refund.

 

Yeah, I'm thinking BIOS, but it says the 5600G is supported from BIOS 1401, which is quite an old BIOS. The latest one is 2407. Obviously I can't check what BIOS version I have, but this board has obviously been sat in a warehouse for some time if it IS that.

 

Managed to get hold of a Ryzen 3100 and flashed it today. That was the issue. Why a "new" board had such an old BIOS I've no idea, but all is well now. Thanks