I'm encountering problems with the power-on self test (POST) of a new build.
CPU: Ryzen 5 1600 YD1600BBAEBOX
Motherboard: ASUS ROG B450-F Gaming
Memory: Corsair 2666: CMK16GX4M2A2666C16
Graphics card: MSI Radeon RX570 ARMOR 4G OCV1
PSU: Corsair RM650X
I assembled per instructions (this is not my first build), and system failed POST. ASUS motherboards have a "Q LED" failure light that includes DRAM (Yellow) and CPU (Red). At startup, the DRAM LED lit for about one second, then the CPU LED comes on and stays on. No POST beep codes. Removing all system DRAM and re-starting (in deliberate fail mode) causes the DRAM LED to light up and stay lit, and beep code indicating "No Memory Detected" activates.
CPU pins are in good order; plenty of thermal paste on cooler.
Is this a bad CPU, or could the motherboard be somehow at fault?