A friendly system i built about 2.5 years ago just died from unnatural causes and id like you're guys input on how to proceed with diagnosing/RMA process.
 
First off here's the system in question:
NZXT 500i
9600k
MSI MPG Z390 Gaming Pro Carbon
EVGA RTX 2070 Black Gaming
Gskill Trident Z RGB 16gb 2x8
Samsung 860 EVO
Corsair TX650M PSU
Cooler Master ML240L
(no cpu or gpu overclocking)
 
So what I've been told right before it died 1 monitor went black with a few colored vertical lines, then a full rainbow. 2nd monitor was fine. He did a restart and the system would not do anything but an audible click when you hit the power button.
 
-I get to the machine and bring a backup PSU with no and confirm the click, no lights anywhere on the board, no fan spin whatsoever. I try the backup PSU and also just get a click and nothing more.
-I had a spare 9600k and mobo so i rig together a test system using his cpu/ram/gpu and i get lights & fan spin but its constantly restarting and not posting. i thought it wa retraining ram but it did this forever.
-I swap in my 9600k and test and i get everything & can post.
 
SO now im thinking that his CPU if dead. and my thoughts are PSU went and took out some parts? The CPU is obviously dead, and im assuming his board is toast also from the no lights or fan spin/anything. I dont want to pull his PSU and test it in a known working system, not a risk i wanna take. The GPU/ram/SSD still could be damaged but limping along.
 
What are your thoughts? Just Mass RMA everything? Start with the PSU?  I could get the test system up and running and maybe fully test RAM with memtest and the GPU in stress tests
 
 
 

I think you did a good job.  CPU and mobo need to be RMA'd.  Can do the PSU if you're worried it's bad as well.  Test his gpu/mem on your current system with something like aida64 and superposition and see if they work fine.
 
You will want to RMA the least possible given the delays and holiday shipping.

Agreed, the clear CMOS was a bit of a Hail Mary. The steps you took were solid.

Did you do a physical inspection of everything? Did you notice any scaring or areas that look burnt on the CPU, CPU socket or anywhere on the motherboard? Where all the cables fine from the PSU? Any singed or melted? If there was a surge from the PSU it often damages the cables. This will be the definitive that the PSU caused the damage.

I would RMA the PSU first. If Corsair determines it malfunctioned, then they should cover the CPU and motherboard. Not sure of their policy on this, but if it was the cause, they should replace the damaged items. How much, I have no idea but I would push for replacement costs.

Need to always have your research done prior to getting the RMA process going.

Got the system running with the spare parts and a quick trip to bestbuy for a PSU.
 
Let Heaven loop a for about 30min and Ran the benchmark a few times, no issue besides some nasty coil whine from the GPU but that was probably always there. Score landed with other 2070's so the GPU doesn't seem hurt. or it works for now anyway. Didn't get a chance to do a memtest yet.
 
The system had a 2nd mechanical storage drive and that IS acting weird. but other than that its running. Time to start these RMA's i guess.

Might be too late to do this , did you do a smell test stick your nose on the parts as in the past I’ve smelt a burnt out psu that was still lighting up but was gone.

Google CORSAIR psu test with a pin to see if the PSU actually works.  You dont have to attach your PSU to any motherboard to test it.
I did have this issue many many years ago with a PSU(s) and a GPU.  YES the psu fried, then a second PSU fried, then I find out that my GPU was the problem, it was sucking so much more power that it actually needed so it fried many psu's and motherboards and 1 cpu. The funny thing is, GPU was functional even the day I RMA it, a very very old gpu if I remember correctly an ATI 2900xt or something.
 
How I find out? This GPU left many dead parts behind. Each time I installed new psu or other parts, you could listen to a very very loud noise coming out from the GPU cooling system and increasing rapidly and then BOOM rainbows and smokes everywhere and when I was playing video games.
Corsair was very polite to let me RMA psus back then, I also got my GTX480 from the ATI 2900XT RMA.
 
I do remember black screens and colors before damaging other parts like PSU's. You remind that experience.