Question CPU contact points damaged?

[And7rey]

Hey everyone,

so basically I bought a used CPU and eversince I installed it, my CPU fan is not working. I'm not sure if it's due to the CPU or the cpu_fan connector is broken, but I got a new fan since and it's not working either, so I had them connected to the sys_fan connector eversince.
Anyways, as I installed the new fan I removed the new (used) cpu and compared it to my old one. I noticed that some contact points are darker and seem to be damaged, but only when I look at the cpu from the an angle. The two CPUs also seem to have a different color for some reason, is this normal in the manufacturing or does it suggest some type of damage or heavy use? The new CPU is working fine, I'm overclocking it and there are no issues, the only thing is the cpu fan not working when it's connected to the cpu_fan connector.

I would be happy if some of you could take a look at this picture I uploaded and tell me if you think the CPU might be damaged.
The left, goldish one is the one I got recently (I5 7600K) and the right one is my old cpu (I5 7500). Thanks in advance!

 

[lvt]

There is no way to tell whether your CPU is damaged by looking at the photo.

You should inspect the CPU after cleaning it with alcohol using a magnifying glass to see if a contact is damaged or a tiny SMD capacitor is missing.

The CPU slot on your motherboard must be inspected as well, one of the copper legs might be bent or broken.

 

[Karadjgne]

Discoloration is normal, it can easily happen just by cleaning the pcb with isopropyl alcohol if someone got sloppy with the thermal paste. It's just color, stain, doesn't affect the cpu.

Bent pins in the socket is a different story.

What motherboard?

 

[And7rey]

MSI Z270 Gaming Pro Carbon is my mobo, it looked pretty fine so I didn’t take a photo.
I might add that this was the first time i replaced the cpu since I built this rig in 2017, and I believe I’m doing everything pretty carefully. Doesn’t have to mean anything, the mobo could still be damaged theoretically but still.
My main issue is basically that the cpu fan is not working when it’s connected to the cpu_fan connector, only when it’s connected to sys_fan. Neither my new fan, nor the old stock intel fan worked on cpu_fan eversince I installed the i5 7600k.
Might be a coincidence, but I’m not sure if the marks on the cpu had something to do with it.
I’m not a professional so I don’t even have magnifying glasses at home unfortunately.

 

[Karadjgne]

I’m not a professional so I don’t even have magnifying glasses at home unfortunately.

Me either. But I do have a cell phone. Make sure your camera is on its highest resolution, get as close as you can and still focus. Cell phones have a zoom function. If there are any bent pins they'll be obvious. 🔎

For the fan, it almost sounds like it's shut off in bios. Pwm fans can spin with as little as a 20% duty cycle, but if bios is set static below that, no spin. Cpus will also detect the no-spin and shut down after a warning, unless bypassed, it's the reason AIO's will have a fan connector there even if fancy enough to be powered and controlled elsewhere.