Maybe check here and see if there's anything missed.
"No POST", "system won't boot", and "no video output" troubleshooting checklist This checklist is a compilation of troubleshooting ideas from many forum members. It's very important to actually perform every step in the checklist if you want to effectively troubleshoot your problem. 1.Did you...
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If there are power related cables that you plug into the power supply (Modular), ie PCIe plug, make sure that side is connected right.
Check the monitor is on the correct input channel. It should auto switch but check anyway.
It does look like the cpu's fan is connected to cpu_fan header, check that it is and not connected to cha_fan,