Question PC fails to post after changing cpu (so signal to monitor)

[Xydian]

Specs:
CPU: i5 9600k
Mothrboard: b365m pro4
PSU: EVGA supernova 650w Gold
Ram: Teamgroup 16gb ddr4 2666mhz (8+8)
GPU: Palit 3060ti

So I bought an i9 9900kf, I tried it with my stock cooler instead of my i5 and everything worked and the PC ran fine. I did not play games with it or benchmark it so it doesn't overheat.

After that I changed to my i5 and then the computer failed to boot and the LED of the graphics card was blinking on and off. Since I only changed the CPU I took it out to check on the socket itself, I found a little piece of grass above the pins and I flicked it off very carefully with the corner of an A4 paper.

I then used the macro lens on my phone to check for any bent pins, found nothing. And then I put my i5 back into the socket and the PC booted fine.


And then I bought a used AIO cooler, the "thunderstorm TS240" from a friend of mine. I assembled it into the case, I switched the i9 into the socket, and the same problem happened. Blinking GPU LED, no post, no monitor output. So I thought something went back again in the socket but after checking with my macro lens there was nothing.

I tried switch the ram sticks around and trying them out in every slot, single, or dual channel, it didn't work, but the LED of the GPU became static instead of blinking. So that is fixed?

And then after turning the PC back again it would light up, fans spinning and everything, shut down for like half a second, and then turns back on again, sometimes it happens sometimes it doesn't (still nothihg on post and no monitor output, although the monitors are listening for the signal).


I changed the i5 back instead of the i9, same problem. I disconnected the AIO and plugged in the stock cpu cooler, same problem. I disconnected the GPU and tried the MOBO HDMI, same problem. I have disconnected the CMOS battery, switched the PC on and off, and then plugging it back again, same problem. Someone told me the cooler was on too tight! HEY! THAT MIGHT ACTUALLY BE THE ISSUE! nope, same problem, no output, every LED every fan is working but no post.

I've tried to find a solution for 6 hours yesterday, doing everything but no luck. My MOBO has no speakers so I can't listen to beeps, I tried hooking up my samsung earphones to the speaker jack in the back of the MB but no sound.

Any ideas? I'm still suspecting the CPU socket, but I need a safe way to clean it from possible dust or small debris resulting in an open circuit between the CPU and the pins.

Edit: I tried the GPU and RAM on my brother's PC and they worked fine. I'm 100% positive that both CPU's are fine. So the problem might be in the CPU socket itself or in the PSU. Although the CPU socket looks fine to me. The struggle continues.

 

[geofelt]

The sockets are delicate.
Normally one does not switch out the cpu many times.
The design specs say up to 15 insertions.
Once the i9-9900KF was working, I think there was no reason to change it out.
As a theory, the pins may have lost their springiness.
Look more carefully at the socket pins, you may have to change out the motherboard.

 

[Xydian]

The sockets are delicate.
Normally one does not switch out the cpu many times.
The design specs say up to 15 insertions.
Once the i9-9900KF was working, I think there was no reason to change it out.
As a theory, the pins may have lost their springiness.
Look more carefully at the socket, you may have to change out the motherboard.

Ok, I just want to make sure that the PSU is working properly before getting a new motherboard. Is there a way to check that?

 

[geofelt]

No good way to test a psu without $5000 worth of testing equipment.
If you suspect a psu issue, borrow a replacement good psu of sufficient wattage.
Your EVGA unit carries a 10 year warranty so I would not suspect it as the problem.

 

[Brokencomputernvrright]

You can take it to a computer shop to test the psu. They have a little tool which doesn’t seem like it costs 5k. The size of a phone with all the motherboard plugs one each side and they simply plug and test. Take all the wires though. We have Canada computers here that does it. US probably had more options.