I have the same issue with new build ROG Maximus XI Extreme
😕 I took battery out / clear CMOS , checked all connections, Tried bios update with USB it sits at AC code when it boots up no error beeps no nothing m/b lights up but nothing ever on my screen for bios. We removed video card tried on board video , tried 4 different screens , made sure L2 is enabled. Tried 2 different video cards , Checked all seta cables swapped them out no joy, reseat ram removed ram left one stick in A2 slot no joy. And cant even get into bios with onboard video. Beautiful build thinking at this point its a bad MB maybe. Full specs below. Any ideas and if I forgot to list other things we tried sorry my brain is freaking out at this point.
Case - Corsair Obsidian Series 1000D
CPU - Intel I9 - 9900K Processor
CPU Cooler - Hydro Series H150i Pro RGB 360mm Liquid CPU Cooler
Motherboard - ROG Maximus XI Extreme
RAM - DDR4 G.Skill Trident Z RGB 4266Mhz 32GB
Tested Latency 17-18-18-38
Video Card - ROG Strix OC 1080Ti OC 1708MHz
SSD's - Samsung 850 Pro X-Three-1TB
Power Supply - Corsair HX 1200i
Fans - Corsair ML120 Pro 120mm Premium x 16 (6 for CPU Cooler push pull)
Command Pro x 2
RGB Fan LED Hub x 3
Corsair LED Lighting Pro Expansion Kits x 2
Monitor - Samsung 49" CHG90 QLED Gaming Monitor 144Hrz 1ms
Bios 602 and did a bios update doh
passed 8hr test on Karhu RamTest
Set to Manual OC
Dram Frequency 4266MHz
Dram voltage 1.45v
CPU VCCIO Voltage 1.25v
CPU System Agent Voltage 1.29v
Dram timing control 17-18-18-38
Mode1
Dram command rate set to 2N set dram current capability to 130%