My troubleshooting steps would probably be:

• Read the motherboard manual to identify any diagnostic features (error led's, etc.)
• Pull out all risers & graphics cards, plug in one graphics card into the full size (16x) slot 
• Connect monitor to this graphics card
• Power on, you should atleast see the BIOS screen now. If no - then you missed connecting something or have a bad component somewhere.
• Is your CPU fan spinning ? Is the CPU power connected?
• Is the graphics card power connected? Does the card need one 6 / 8 pin or both 6 + 8 pin to be powered

Sorry if this is a noob question but any inputs on how to get the POST screen to show up consistently from a particular HDMI output would be appreciated. I could not find anything searching on google or in the motherboard manual.

Microcenter in chicago has 4 in stock at 300$ each. Thats double of what it was a month ago. That negates CPU and RAM savings for anyone thinking of getting one of these boards now.

Maybe they will go on sale soon.

Currently running ten cards on this motherboard and am having trouble getting number eleven to work.

My setup:   Have not connected Molex power connectors onto the motherboard since I am using powered  PCIe 1x -> 16x risers.

• 16 GB of RAM, Win 10 64 bit Professional, Intel i3 processor
  
• Not using the PCIe 16x slot since I was having trouble with the riser cable (long ones were too expensive  )
• The first bank of six PCIe 1x slots is running RX 580 cards
• The second bank of PCIe 1x slots is running two RX 580 cards and two 1070 cards

This configuration was stable and mining 24x7 until I got four additional 1070 cards last night. I like adding cards one at a time so I am focused on getting the 11th card working now. What I'm seeing is that the fan on the new cards spins up for 20 seconds and then shuts off. The card does not show up in device manager after windows boots up.

Also not seeing the POST screen that shows the status of each slot since my monitor stays blank until the system boots into Windows. I have found that connecting my monitor to a different card will display the POST screen but it seems to move around!

Question 1:Is there a BIOS setting or other way to reliabily get one particular graphics card / HDMI output to show the POST screen since its the best feature of this motherboard?

Things that I have tried already to get my 11th card working are:

• Swapped out the riser
• Swapped out one of the working 1070 cards with the new card (all other connections remained unchanged) - this resulted in the new card getting detected

Question 2:Any leads on what else I can try to get the 11th Card (3rd 1070) working? It looks like something in the BIOS / MB is preventing it.
Question 3:Do I need to hook up a third power supply for when I get to Card 13 and 14 (power draw wise I think I am ok)? But will using the third bank of slots require a 3rd PSU ?

Thanks in advance for your help.