X99 MB does not post after proper shutdown

Symptom:
PC will not power up after a two week period powered off (did an OS shutdown, switched off PS, left power cord plugged into UPS). Only lights that appear ?œon??are the lights from the built in network card.

Facts:
1.     Power supply is working. Removed 24 pin connector and shorted two pins to get Fans to run.
2.     PC was working just fine for 24 months and until I shut it down and went on vacation for two weeks.
3.     Sleep function never worked so I stopped using it and left it powered up always. The sleep function would exhibit the exact same symptom described above and recovery step 1 or 2 wakes it up again.
4.     MB is 26 months old (two months out of warrantee)

Things I tried:
1.     Shut off PSU switch, in-plug power cord, wait 1 minute
2.     Remove 24 pin PSU connector and short PINs to run Fans, and plug back into MB
3.     Removed GPU and tried booting
4.     Removed USB connections to MB and tried rebooting
5.     Removed all SSD and Hard-drives and tried rebooting
6.     Removed all other connections to MB including CPU power connector (just to see if something would light up
7.     Used Reset and Power buttons on the MB
8.     Reconnected everything and tried again
9.     Shorted Power PINs on power header (to rule out power switch)
10.     Reset CMOS post step 1 (knew this wouldn?™t help but did it anyway)
11.     Replaced CMOS battery post step 1 (knew this wouldn?™t help but did it anyway)
12.     Repeat steps 1-8, 3 times
13.     Reviewed all steps here http://www.tomshardware.co.uk/forum/261145-31-perform-steps-posting-post-boot-video-problems?_ga=2.3753206.756449800.1514909491-1631549645.1447305133 (but this is mostly to do with a new build not coming up)
14.     Switched to BIOS-B and tried rebooting
15.     Read a lot of similar problems on this forum.

Theories:
1.     The ASROCK X99 MB has some type of power-caping limit that triggers on some voltage threshold that locks it from booting (step 11 should have cured this), once this latches it never in-latches. Also why it could never recover from sleep correctly.
2.     The ASROCK X99 MB is bad, but have no idea where it is bad

Questions:
1.     Does anyone have a good recommendation for a MB tester that actually can pin-point a problem, most I have seen report POST codes which isn?™t useful if it never actually POSTs.
2.     Any other diagnostic test recommendations I can do before I either RMA or purchase a new compatible MB and start all-over rebuilding the PC and re-installing an OS?

PC Build:
https://pcpartpicker.com/user/GeekWon/saved/#view=dZq8TW
Boots Windows 10 off of M.2
RAID 0 with two 3TB 7200 RPM drives for general storage
1 TB drive SSD for programs and data