AB350 Pro4 + Ryzen5 1600x won't post

This setup was working for a year and stopped working abruptly.

ASRock AB350 Pro4 AM4 AMD Promontory B350
AMD RYZEN 5 1600 6-Core 3.2 GHz (3.6 GHz Turbo) Socket AM4
GeIL SUPER LUCE AMD 16GB (2 x 8GB) 288-Pin DDR4 SDRAM DDR4 2400 (PC4 19200)
EVGA 600 B1, 80+ BRONZE 600W

The power supply seemed to stop working - would not turn on at all - no fans, no lights, etc. Totally dead.

So, replaced the PS with another working one.
PS lights up. All fans come on. Graphics card lights up. RAM lights up.
But no post at all. Monitor goes into sleep mode.
I don't have a motherboard speaker to test.

Tried clearing CMOS using both pin shorting as well as removing battery for 5 minutes.
Reseated CPU.
Tried without M.2 and hard drive. Tried without RAM. Tried different graphics card.

Removed motherboard from case to make sure nothing was touching/shorting.

So, it seems like it's the CPU or the board. Maybe the original PSU blew something?
It's under warranty - will return to eVGA, but that doesn't explain current problem.

Any other ideas? Purchased everything new from Newegg in 9/17 - has been working since.

Other thoughts?

Thanks.