First TrueNAS build: Powers on but won’t POST (ASRock B550 Pro4)

[QuestionAsker]

My new build powers on (fans spin, LEDs on) but no POST / no video output.



What I’ve tried / observed:

• System powers on normally (fans, LEDs).
• No signal on monitor (HDMI/DP).
• No POST screen, no beeps.
• Tried booting with Ryzen PRO 4750G, and then with Ryzen 5 3600 + GPU… still no POST screen or anything

Hardware:

• Motherboard: ASRock B550 Pro4
• CPU (primary): Ryzen PRO 4750G (used)
• • One pin was bent when removed (now removed from system)
• CPU (test): Ryzen 5 3600 (used)
• GPU (with 3600): Gigabyte Radeon R9 390X
• RAM: 64 GB ECC UDIMM (2×32 GB Kingston KSM26ED8/32HC)
• PSU: Corsair RM850x

Notes / hypotheses:

• Suspect BIOS incompatibility with 4750G or damaged CPU pin.
• Even with Ryzen 5 3600 + discrete GPU, still no POST.

Next steps I’m considering:

• Test with a second (older) GPU
• Attempt to straighten the bent CPU pin on the 4750G (though it’s my first time doing that and I’m a bit nervous… it looks pretty bent)

Question:

What else should I try to isolate the cause (BIOS, RAM compatibility, board issue, etc.)?

 

[Aolish]

Usually whenever I'm confronted with a black screen and no post, I just go straight to the ram and reseat or remove one of them. Try that and see if that works. But if your CPUs pins are really bent then that can definitely cause a no post. Try both.