Question New Computer build won’t post, flashes on flashes off


Mar 3, 2021
Building a new computer
Flicks on then off, repeatedly. After I turn off the computer, RGB ram sticks light up.
rough build, can give exact components if need be.
Msi-790 motherboard
Rtx 4090
Couple nvme sticks
Enermax liqmax 3 cpu cooler (just using cooler hooked up to pump pins on motherboard directly)
Using system fans not fans with Enermax. Forgot to hook up led of Enermax)
1250 watt psu segotep
EXACT components please, including EXACT power supply model and how long that unit has been in continued service?

CPU, motherboard, memory kit, power supply, graphics card, exact drive models, CPU cooler. General descriptions of parts do not solve problems. Knowing EXACTLY what we are working with, does, at least, a lot more often.

Also, you can't just use the CPU cooler however you want. If it offers an option for a direct connection to an AIO pump header rather than specific purpose built connections, that is fine, but you probably ALSO must have the radiator fans directly connected to the CPU_FAN header or else the system is never going to want to boot if it sees no CPU cooler RPM signal. It will just turn on and turn directly off again. That is of course if your radiator fans connect directly to a fan header rather than to a plug on the pump waterblock assembly and if that's the case you may need to connect the AIO pump connector to the CPU FAN header rather than an AIO header if that is how it is now. By default a lot of BIOS will not allow the system to remain on with no RPM signal on the CPU FAN header. It can be disabled in the BIOS so it doesn't do that, but you have to GET there first, IF that is the problem.

At this point it's probably also a good idea to try to POST with NO drives installed or attached, and if your CPU is not an "F" model, and has integrated graphics, then also without a graphics card installed and with your display cable connected to one of the motherboard video outputs in order to eliminate some potential sources of the problem.