Question Installed a new CPU cooler on old PC then it won't boot, no display signal, fans running

[garbage_eater]

So I bought a new CPU cooler, excited to install and use it instead I'm met with disappointment because it will not turn on anymore. It was just running fine the day before.
Fans are running.

Basic specs
CPU is Intel i5 3470
Mobo intel db75en
GPU 1060 6gb
Uneven ram sticks

Cooler is thermalright ax120r se air cooler, I had to take out the mobo to install the back plate for intels case. I cleaned the GPU and mobo with compressed air while I was at it, not sure if this could have done something to it?

I then cleaned the old thermal paste in the slot without taking the CPU out the socket and putting new thermal paste on it and installed the cooler as instructed. When I finished I put everything back in the case and then it happened, won't boot.

No display signal, no beeps, fans running. Mouse light running at first but now it only lit up for a few seconds before turning off. No keyboard lights.

What I've tried: (pretty much everything I could find on internet)

Reseated gpu
Reseated cpu
Reseated psu power cables
Changed up ram slots, reseated them etc
Using only 1 ram stick
Taking the ram sticks out, hear 3 beeps for missing memory as normal
Loosening heatsink
Take out the CMOS battery
Using a different battery
Reset CMOS
Using other GPU from different pc
Tried other monitor from a different pc
Tried another psu
Tried both psu with other pc, booted to bios just fine there
Taking out mobo and stuff out of the case and try (Breadboarding)

Etc.


So I've eliminated a lot of components but still not sure about two, CPU and motherboard. But really confused because I didn't take out the CPU out of the socket when installing, and I don't see any blown capacitors or chips or whatever on the mobo. So I really don't know what could have happened when it was just fine the day before. It's hard to test the two parts because they are so old and incompatible with new stuff.

I will try uploading pictures of the CPU and socket and put more info here, posting from the phone

Socket lga 1155
https://media.discordapp.net/attach...6/1128659334839152670/IMG_20230710_224618.jpg https://media.discordapp.net/attach...6/1128659578452713552/IMG_20230710_224652.jpg https://media.discordapp.net/attach...6/1128659579169931354/IMG_20230710_224723.jpg https://media.discordapp.net/attach...6/1128659579773911080/IMG_20230710_224733.jpg

CPU- Not sure what the mark is or whether it had been there before. Is it fried?
https://media.discordapp.net/attach...6/1128660303291359232/IMG_20230712_191139.jpg https://media.discordapp.net/attach...6/1128660303551418468/IMG_20230712_191214.jpg https://media.discordapp.net/attach...6/1128660304256061552/IMG_20230712_175555.jpg https://media.discordapp.net/attach...6/1128660303882752030/IMG_20230712_191241.jpg

Ask if you have any questions. Thanks in advance.

 

[NanoSuit3]

That CPU is probably fried/dead with that scab or scratch; happened to me before with an i7-6700 back in the day. Came faulty out of the box; didn't know so sent it back, got a K version instead cuz offered it..................... So.................... Unless you can get yourself a separate Mobo to test it out for sure I'd say........................70-90% Ooooooooooooof..............................

 

[garbage_eater]

That CPU is probably fried/dead with that scab or scratch; happened to me before with an i7-6700 back in the day. Came faulty out of the box; didn't know so sent it back, got a K version instead cuz offered it..................... So.................... Unless you can get yourself a separate Mobo to test it out for sure I'd say........................70-90% Ooooooooooooof..............................

Thanks for the input
That's unfortunate if it's the case. I've no idea what how or where/when it happened 😭
I could try getting a second hand one online to test it out but at this point I'm not sure if it's worth it anymore

 

[NanoSuit3]

Never know. Get your hands on a decent Mobo; might work out.

 

[garbage_eater]

Not sure how easy it is to find a mobo that old, probably easier to try with a second hand CPU?

 

[garbage_eater]

Also what's curious is the mouse light, it was appearing like normal at first (even with no display) then it's gone entirely now I think?

Edit: it still appears for 1-2 secs before disappearing, I just didn't plug it in.

 

[thestryker]

I'm not sure if this is why you're having the problem, but there are definitely damaged pads on the CPU. The motherboard looks pretty clean so if you want to try to get things working try to get a CPU as long as it's cheap enough. It looks like your board should support pretty much anything from the 2nd/3rd generation so long as you have cooling.

 

[garbage_eater]

I'm not sure if this is why you're having the problem, but there are definitely damaged pads on the CPU. The motherboard looks pretty clean so if you want to try to get things working try to get a CPU as long as it's cheap enough. It looks like your board should support pretty much anything from the 2nd/3rd generation so long as you have cooling.

Thank you! Yeah there is actually another blot of damaged parts on the opposite end thats a bit smaller than the ones shown, I just noticed it later so I didn't take a picture of it, it's very hard to notice and not sure if it was there earlier either. I'll try finding a cpu.

 

[garbage_eater]

So I bought a used CPU now, it still shows no display. However the mouse does light up normally now, so the old CPU was probably actually dead/problematic. Now, I still have no display signal, even when trying with old VGA+hdmi adapter plugging into my motherboard to try to boot with igpu, still no display.
However the weird thing is, my monitor will always say "display port - no signal" despite not having the DP cable plugged in at all, when using hdmi to hdmi or VGA+adapter. My monitor is gigabyte g24f.

 

[garbage_eater]

Tried moving the GPU to my dads pc and it still works. What the hell. Is the mobo dead? Currently I have everything except storage in breadboard form, i dont need storage to POST, right?
Edit: now I don't see the mouse light up anymore... What is going on

 

[garbage_eater]

Update (late): I figured it out a month after posting this. So, apparently I did (almost) everything right. It's just that the Intel motherboards, you know, stuff they don't make anymore, have a somewhat weirder layout than other brands let's just say. And with that, information on such archaic things are harder to find these days. I had to read about the clearing CMOS with the jumper on other sites that are not intel and check the manual again.

So how you would reset the CMOS via the jumper is different on intel mobos, at least on this model. There are not just 2 pins but 3 pins (pic above). So to reset CMOS with jumper you need to short no. 2-3 pins, using a jumper cap or screwdriver or w/e. But not only that, afterwards, in order to post and boot normally you need to short the CMOS pins before power on but on NORMAL mode (number 1-2 pins in pic), otherwise it will go on "recovery mode" but is just no post black screen for me. This is the most important part I was missing.

I still don't know how it was booting normally before I took it apart, I didn't have jumper cap on it, maybe there was something that was plugged in to short it. But I have since changed the case.
Mystery (mostly) solved, I guess. Thanks all for trying to help.