Question Burnt MOBO, maybe PSU

[incompet3nt]

so ive had this rig i custom built 4 - 5 years ago that has worked totally fine up until about a week ago. it was freezing, crashing, refusing to start. ive taken it apart fully now after struggling to find the problem for a week (prob spent like 15 hours total trying to fix).

i see now that the 8pin on the motherboard connecting the EPU and PSU has burnt and melted one of the pins (dont know how or when). a little bit of plastic stuck melted inside the EPU socket and some brown burn marks on the top 4pins. it was a bit of a struggle taking the cord out but i was able to do it with no further damage to the cord or motherboard.

now the computer was surprisingly still sort of working, it atleast wouldnt crash immediately. i even got 2 hours of gaming in when i was testing what triggers the freeze/shutdown.

id imagine this means the PSU isnt damaged since it was supplying power to the CPU (even through the messed up socket), the SATA cords for my hdd and ssd, fans, cpu cooling unit, pretty much the whole pc.

What do u guys think i need to replace? just the EPU socket itself (if possible), the whole motherboard, or the PSU and motherboard

 

[rolli59]

Post your full system specs!

 

[PC Tailor]

Welcome to the forums my friend!

What is your PSU make and model?
You will need to replace the motherboard.
You'll probably need to replace PSU too as this probably caused it (Especially if you have a poor quality PSU)

 

[incompet3nt]

Thanks for the warm welcome!

Here are the specs btw

PSU: Corsair RM 650x
MOBO: ASUS M5A99X EVO R2.0
GPU: ASUS Strix GeForce GTX 960
CPU: AMD FX8320
CPU Cooling Unit: Corsair H80i GT

Thanks for the help!

 

[rolli59]

PSU is a quality one so do you see any damage to the connector on it or is only on the motherboard connector?

 

[AllanGH]

What generally causes what you observed as burning, is high heat between the PSU harness connector terminals, and the MB connector terminals, and that heat is caused by increased resistance between the two terminals in every circuit that shows signs of high heat.

This can be just a matter of aging, and the fault mode is usually the socket terminals losing tension, and not gripping the pin terminals with enough pressure to maintain low contact resistance. It can also be caused by low-quality socket terminals; however, if you got 5 years out of it, that's likely not the case in this instance.

In general, the proper repair would be to address the side that has the socket terminals--meaning that you would remove the old socket terminals and replace them with new. But, to affect a complete repair, you would also replace all of the pin terminals as well.

 

[AllanGH]

In looking at EPS cables that I have laying around, the terminals appear to be AMP MATE-N-LOK pin and socket types, which are commonly available in the retail market.

See: Datasheet

 

[incompet3nt]

Thanks for the advice everyone, youve all been very helpful. i took the psu and cpu into canada computers for them to test on other rigs since i dont have any other ones. just got back from them today and they said no problems with either.

So now im super confused as to what happened. is it quite literally just that the socket terminal wasnt tight enough on the pins? id imagine this would be a result of constantly expanding and condensing because of temperature changes over the years. what do u guys think?

Now onto the decision i should make. should i ditch the motherboard and replace/upgrade? id probably upgrade since the old one is ddr3 and i foolishly bought 8gb of extra ram... in ddr4 lol

 

[AllanGH]

id imagine this would be a result of constantly expanding and condensing because of temperature changes over the years.

Exactly.