Mike UK

So the 2nd and 3rd power supplies were fine and didn't/don't need to be returned.
 
It's pretty obvious that it's marker drawn on the connector and not burn marks. If the cables were burned I would expect to see the actual plastic housing of the pins melted, possibly the plastic coating on the wires too. Likely also damage (burn marks, melting) to the connector socket on the motherboard as well.
 
Given how your motherboard fried itself I imagine you were expecting to see burned cables, so I can understand why you might have mistaken the discoloration of the marker for burn marks on the first power supply cables. Most people probably don't look that closely at their connectors or expect to see burn marks on them so they likely just never notice sharpie markings like that.
It is disappointing that Corsair support didn't pick up on this, at least with the 2nd and 3rd unit you contacted them about. There should have been no need to return the 2nd unit if it was handled better and it wouldn't have needed to drag out for so long to get a resolution, but we also don't know what was said to support either and if you just told them "I got my PSU and the cables are burned" then they can only work with the information they have.
 

Looking at the photos in that first thread the motherboard is definitely fried. Unclear whether it was the power supply that fried the motherboard or if the motherboard fried itself. Looks like it is plugged in correctly and those are the correct Type4 cables, I can't see anything that stands out as having done anything wrong in regards to building the PC. It's unfortunate to happen to a new builder but in some rare cases parts are just dead on arrival and it's not a matter of doing anything right or wrong.
 
You should be able to replace the motherboard through ASUS as that damage would be covered by the motherboard warranty.
 
 

CcRAcHPXIAE22wF.mp4

Stayed on some window? Did you try stress testing it? Play a game or something? Make sure all it's functions still work?

Post a few responses by the CEO's, share with us this amazing customer service you get?

Dash cam, dented box, Walmart executive support:
 
Walmart again, not sure what this was about:
 
Amazon, defective battery charger:
 
Wahl, electric hair clipper had rust on blades. Direct ceo response:
They upgraded me for free. 
 
Home Depot, 35% spec discrepancy (misadvertisement) on an air purifier:
 
Dell, laptop that I didn't like, past the return window:
 
Can't find my other Dell emails from 2016 but their executive CS has hooked me up with replacement parts several times, no questions asked. DeWALT sent me a $300 LDM & laser level kit because a stud finder I bought from them broke - on top of sending me 2 upgraded stud finders. I tested them on myself, naturally, they work. Verizon has helped me immensely over the years and has some of the best executive support I've ever worked with, making some major exceptions to their standard practices that regular CS isn't authorized to.
 
There are countless others. Many of which were resolved over the phone and not email.
 
Last time I RMA'd something it was a Radeon VII to MSI and they kept it for 2 months, made me pay for shipping. Lmao.
 
But no, you go ahead and just RMA stuff and move on with life. Because that's totally better. 

looks like poor connections on the mobo. rma the mobo get a new one.

May find something useful here.
 
https://superuser.com/questions/1344448/8-pin-cpu-power-connector-has-different-form-on-one-end
 

ASUS
Mr Samson Hu CEO     Email samson_hu@asus.com     Telephone +1 510 739 3777  
Tech companies are hit or miss IME. Worth a shot though, I've never dealt with ASUS. Or bought anything from them, for that matter.
 

I am the chap he brought it to. Hi Mike!!!
 
It's a 4+4 connector, however I have not seen a connector such as this with additional keys, The PSU end of the cable has the correct keys but the motherboard end has more chamfered than I would normally see. The cable is the correct way round as the cable retention clip can only be secured one way. I wasn't sure if this was a corsair quirk and was a little suspicious of the cable as this was accompanied with a component failure on initial start up. I have identified two possible causes. The motherboard component failure was under one the heat spreaders and could have been caused by a damaged MOSFET (either bad anyway or crushed through overtightening at the factory) or PSU issue but I didn't bother too much with that. 
 
Probably nothing and I doubt anyone would have ever noticed if not for the smoke. Do corsair normally make them like this or should I get my multi meter out before we drop another board in?
 
 
 
 

Yeah it's not unusual to have all the pins on the right half with rounded keying. It doesn't have to match the plug as rounded pin goes into square pin fine.

Lol, I contact the CEO whenever possible for literally any problem I have with any product or company. It's always executive level customer support and it's fantastic.

That really sucks, sorry you had to start this way. From everything on this thread it's pretty clear the mobo or PSU was faulty so you should be able to RMA those, hopefully nothing else was damaged. I certainly know the sick feeling when something you put a lot of time and money into doesn't work, it's not a very nice feeling. 

Is it just me or does this look like there is a thin layer of solder covering everything to the left of the plug? In which case that is definitely a manufacturing problem and should be returned without issue.

 

Definitely contact the CEO of a large manufacturing company when one of their products has a fault.  /s
 
Never had anything break on you, have you?  Return it, move on with your life.

This just goes to show the complications of building your own PC. I built my first one last year with an 8700k. When something goes wrong, especially like this where it could have affected multiple components, it makes it much more complex of a matter to take to customer support.
 
Also when it's anything short of a highly common configuration, there are inevitably some random weird issues that are difficult to troubleshoot/resolve.
 
I'll probably never build a PC again myself.
 
Best of luck resolving this, sir. Looks like a pain in the ass. I'd recommend searching the CEO/corporate contacts for whatever company you find to be responsible and contact them first. Speaking from experience, that might make it a bit easier.

The potential damage to other parts is possible such as CPU, RAM, etc. 
 
Other than replacing motherboard, consider swapping the power supply as well. 
 
Sorry to hear about this happening to you and during your first build, too. 

I don't know, it almost looks like one of the PCB layers has shorted if you look carefully.  Over-tightened heatsink screws during manufacture?  Unless something is actually shorting on the other side I can't see anything an end-user could have done to cause this.

I'd take the motherboard out of the case, take photos of both sides where its burnt.  Trying to figure out where it started could be a clue, although either way I'd be returning it and praying the CPU is okay.

Good catch, yeah looks fine.  Did I mention I hate everything being black as its so hard to get a clear photo of? ?

Did you happen to drop a screw anywhere while building it? It's possible that a dropped screw could have caused a short.

RMA is Return Merchandise Authorization.  Basically you call them and say their shit is broke, return it and they verify it was their product malfunctioning.  They send new one.
 
 

Looks like a 4+4 so the correct cable, although it does possibly look like it's upside down?
 
EDIT,  Looks like it's just the clip for keeping the 4/4 together, not the latch to hold the plug in.

can i ask you something? what psu did you use?

I don't see the catch on that 8pin socket, did you plug it in upside down somehow?  Is that definitely the 12V CPU connector not a PCIe one?

This is why I HATE black cabling, you can't see the polarity/voltages of the pins at a glance.

Yeah< RMA that board.  Looks like the soldered connections under the 8-pin were manufactured badly.  Or that's what I would claim when I set up the RMA.
 
If you had standoffs and plugged in the 8pin properly, not much else to do.

Did you remember to install the motherboard standoffs? If you didn't, then the motherboard shorted out on the back of the case.

Looks like the cable was plugged in correctly.  I see standoffs as well in the pic you just posted, so that's not a problem either. 
Looks to me like there was a problem with the 4+4 connector on the motherboard, but it could also be a problem with the power supply or the cable itself. 
 
If you bought the parts in a computer store, I'd take it there and let them verify that the power supply and cable work as intended and that the CPU still works.  Once they find out which part caused the problem, that manufacturer should be liable for any damage to other components.   
 
If you bought everything online, I'd go to a repair shop anyway so they can identify the culprit and tell you the extent of the damage.  It's better to pay $50 or so to a professional to get a proper diagnosis than to spend days on it yourself and possibly spend a lot more money on buying replacement parts you don't actually need. 
Once the shop has had a look at it, take it up with whoever you bought the parts from or get in touch directly with the manufacturer.