[SOLVED] PC shut down, wont boot up again

[Ginfners]

My self built PC was running fine for about 9 months when it suddenly shut down in the middle of gaming. Tested the psu on my old pc and it worked, tried everything with cmos, so I suspected the motherboard died and sent it back since it was still under warranty. Got a replacement and same problem, so I sourced a third motherboard and a new psu to try get to the bottom of this puzzle, and I'm more confused than ever. I've been testing and swapping parts all evening to try find the culprit. Apologies in advance if this gets confusing. I'll try make it as clear as possible. I'll list what I have to try help make things clear:

CPU - AMD Ryzen 5 1400
RAM - Corsair CMK8GX4M1A2666C16 Vengeance LPX 8 GB
GPU - XFX Radeon RX 570 RS XXX Edition 1286MHz, 8gb GDDR5
Motherboard #1 (now returned) - MSI B450M BAZOOKA
Motherboard #2 - MSI B450M BAZOOKA V2
Motherboard #3 - ASUS PRIME B450M-A
PSU #1 - Corsair CP-9020101-UK CX450M 450 W
PSU #2 - Corsair VS650 650 W
Case #1 - Thermaltake Versa H21
Case #2 - Not sure. It's from a much older that my build replaced

So like I said today I tried various combinations to see what would work. I put the third motherboard into case #1 along with all components, and nothing. Took everything out and tried just the psu #2 and case fan. Nothing.

So I put motherboard #2 into case #2, to test if maybe the problem was the power switch connector on case #1. Tried just the motherboard and case fan... nothing.... until I lift the cpu lever. Then there's power and the mobo lights up and the fan spins. But once I try add the cpu and heatsink, basically once the cpu lever goes down the power just stops and nothing happens. Tried the same thing with the cpu lever on the mobo in the other case and... nothing. And out of curiosity, I tried the power switch connector from case #1 on mobo #2 and there's power.

Frankly, I'm baffled by all this so if anyone can figure out the logic of what might be the problem from this information I'd be very grateful. The CPU seems to be the most likely problem from what I can tell, but that still doesn't explain why mobo #3 wont power on, unless it only powers on when a working cpu is attached (odd?), or it was doa also and I'm having awful luck.

Thanks to anyone that took the time to read all this haha

 

[Calvin7]

PSU #1 does not have the required power to run the video card.

Lifting the CPU lever with the power on. I wonder if you have any CPU cooler on and are running a bare CPU. You may be short circuiting the CPU by partially removing it with the power on.

The mobo lighting up and the fan spinning may work by only connecting the 24-pin power connector. Disconnecting the 8-pin ATX 12V power connector does the same thing as removing the CPU by lifting the release lever.

Short circuiting the CPU is caused by electrical power jumping across the wrong pins as the CPU is being removed. Running without any thermal solution on the CPU can damage the CPU in a matter of seconds.

 

[Ginfners]

Thanks for your reply. I am using a CPU cooler and thermal paste anytime I try adding the CPU. I only tried powering on with the CPU lever up when the CPU and cooler were removed. Once I add them, there's no longer any sign of life or power getting to the motherboard.

 

[Ginfners]

Sorry for the bump, but just wanted to give an update for any time-travellers that stumble on this thread with a similar problem. Turns out I needed a new CPU after all. So, CPU failure may be rare but it can happen