PC not starting unless I reseat motherboard power.

[NoisyBoots]

Hello,

So I just built a new gaming rig.

7850x CPU
Gigabyte B650 Aorus Elite AX
Corsair Vengeance DDR5 32gb ram
MSI 4090
Corsair 1000w power supply
Corsair AIO

Finished build and it wouldn’t turn on, fans would spin for a second and stop, but RAM would light up. Thought power supply, swapped cables and tested on other supply, same problem, checked stand offs and screws, all were good, still no power. Ended up going in reverse and testing, took out gpu, moved around ram and tried with one stick in, tried with different ram, all the same. I unplugged mobo power and plugged it back in and tried and got it running. No problems after that but any time I turn off computer completely I have to unplug and plug mobo power back in and it will start fine. Computer will restart fine without having to do this. Not really sure what else to try..

TIA

[Bruce]

I would suggest stripping it all down and re-assembling on a piece of cardboard on a table.
it’ll eliminate any potential shorts, and make you double check all the connections as you rebuild.
plus, with it all exposed on the cardboard, it makes swapping parts so much easier.

as you re-assemble, also check the compatibility of all the parts.
also, only re-assemble the core components to get into BIOS initially, so no mouse, no DVD, no GPU, no drives, one RAM stick, no external USB devices - that sort of thing.
if that works, then add stuff to get into Windows - add the mouse, the drive, and test.

keep it simple, add one thing at a time.

[NoisyBoots]

Problem solved.

Weird enough I think it was the AIO pump unit. I did the tear down and it started fine, started rebuilding and testing after every component then the problem started again after I put the AIO pump on. I loosened it just a little bit and now its turning on normally and has turned on fine from completely off multiple times. I really didn’t want to tear it down again but doing one thing at a time like you said helped me find the culprit.

Thank you!

[Bruce]

woo-hoo.
a win is a win.

good job on the strip down and rebuilt.

will close as solved.