ASRock X370 Killer SLI/ac - No POST

For troubleshooting, I have disconnected everything from the motherboard except power to the motherboard itself and power to the case fans and the Corsair H100i radiator cooling system (http://www.corsair.com/en-us/hydro-series-h100i-extreme-performance-liquid-cpu-cooler).

My HDMI monitor is connected via the onboard HDMI connection. No video card is presently installed. The monitor and cable both work perfectly with another computer.

My ram (Corsair CMK16GX4M2Z2400C16) is approved by ASRock (http://www.asrock.com/MB/AMD/X370%20Killer%20SLIac/index.us.asp#Memory) and by AMD (https://www.amd.com/system/files/2017-06/am4-motherboard-memory-support-list-en_0.pdf). I have tried two sticks (which is all I have) in A2 and B2, two sticks in A1 and A2, two in B1 and B2, one stick only in A2 and one only in B2. According to this sticky post http://forum.asrock.com/forum_posts.asp%3FTID=4565&title=am4-ryzen-specific-memory-and-tips when using two sicks, they go in A2 and B2 only. According to the manual (http://www.asrock.com/MB/AMD/X370%20Killer%20SLIac/index.us.asp#Manual) if using only one sitck, it goes in A2. I've tried both sticks (one at a time) in A2. When installing RAM, I have applied support to the back of the motherboard when inserting RAM to be as sure as possible that the DIMM is 100% fully seated in the slot. 

My CPU is an AMD Ryzen 7 1700X Processor (YD170XBCAEWOF).

My power supply is a EVGA SuperNOVA 650 G2, 80+ GOLD 650W (220-G2-0650-Y1).

When I power on the unit, the LEDs on the motherboard (under the shielding over the AMD Promontory X370 chipset) briefly are green, then switch to a slow pulsing red (heartbeat?). 

There are no beeps when the unit is powered on. No beeps are produced by the monitor or on a set of earbuds plugged into the onboard speaker jack (green). If there's an onboard speaker (like on an ancient IBMS XT mobo, for example), I sure don't see it or hear it. Unless the beeps are turned off in BIOS by default, I should hear some sort of beep code if there is an error condition, i would think. I can't find where beep codes are documented in the manual or on ASRock.com, but this site (https://ddr4motherboard.com/beepcodes/ASROCK-X370-KILLER-SLI-AC) purports to list the beep codes for this motherboard. Again, I hear nothing when it boots.

I have removed the CMOS battery for >20 minutes (more than once). 

I have shorted pins 2 and 3 on the CLRMOS1 block for >5 seconds (more than once) then returned the jumper to pins 1 and 2.

I have read every post on this forum where people with X370 boards and no-POST is discussed. I believe that I have tried everything that anyone has posted worked for them.

I'm all out of ideas and I still don't know whether I have a bad motherboard, a bad Ryzen CPU or both or neither. I don't know what to do next.

On my honor, I promise a six pack to the knight in shining armor who can help me to get this working. 

I had a problem with Killer SLI non AC with no post. Sapphire 7950 Vapor-x was in the 1st pci-e slot and there was no way to get post screen. With 1.6 bios even speaker is not working i didnt know whats going on.

I got post only when GPU is in 2nd pci-e slot. After bios update to 3.1 speaker worked (5 long beeps) but the problem is still there, no post. 2nd pci-e working fine. Tomorow i got Zotac 1070 amp extreme and its working in 1st pci-e just fine.

I lost 12h trying to find a solution, searching on internet... Lots of people had a no post problem and didnt find a solution.

One more thing, I cant restart my computer. If i restart it wont post, just get stuck. I have to shut it down and power it up again.