[SOLVED] I've put a floppy cable in the fan header

fr0sst

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Aug 26, 2017
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Yesterday I was upgrading my PC's CPU to a Ryzen 7 5800x, and I noticed a loose cable. I was tired and put the cable in the fan header, which was just barely long enough to fit in. With my half-sleeping head I didn't notice it was the floppy cable and when I put my PC on the port was smoking and glowing. When I realized it was burning, I put the I/O switch on the PSU off. I pulled it out and tried to put it on again, but it was smoking again. Damn, I've just fried my motherboard, I thought. It didn't turn off both times, and if it didn't smoke or so I would have thought it would have started normally. It's especially stupid because I've assembled a few PCs before and I am fully aware it is floppy cables shouldn't go there (or anywhere). I accepted that I should buy a new mobo, but I wonder if it did any damage to other components.

After the incident, I've disassembled everything and did a close inspection of the board. It only seems the fan header is burnt, and the heat discolored the eight-pin connector's edge. For the rest everything on the MOBO seems normal, I tested my SSD on my laptop which works fine, I've tested my PSU with a cheap AliExpress tester which gave the following results: 12.0 -12V, 11.9 +12V2, 4.9 5VSB, PG 300ms, 4.9 +5V, 11.9 +12V1, 3.2 +3.3V. The LEDs on the left didn't turn on as expected, the +12V led only turned on with the molex inserted and the +3.3V and +5V only with the SATA. Again, it's a cheap AliExpress thing so I doubt it's reliability. The other components aren't elaborately tested except to see if there's physical damage. There isn't physical damage. Probably I should go to a neurologist to see if I've got brain damage.

Do you guys have any input whether if components could be damaged as well, or is it just my mobo? Thanks in advance!

Specs for my mobo and psu:
Corsair RM650x (brought it in 2017)
Gigabyte x570 aorus elite
 

fr0sst

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Aug 26, 2017
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You'll have to flash the latest BIOS in order to boot that CPU. Read the manual to learn how.

If it's truly fried thats an expensive lesson learned.

I'm curious as to why you have a floppy cable at all?

Thanks a lot for your response,

I've flashed it, which I assume worked. The issue is when I removed the floppy cable it started smoldering and smoking again. I don't know if it's truly fried, I kinda assumed it is, but I know the possibility the damage is limited to the header itself is there.

I am not sure why it was there, but I am 95% sure it came with the PSU as the case fans are powered tothe molex the floppy cable was attached to. I just didn't bother to remove it back in 2017.

Edit: I must add I went from an Intel i5 7600k to a Ryzen 7 5800x, so I brought a new mobo as well. The 'loose cable' I've mentioned was on the back of my case where it just dangled, pre-installed to the molex. It was unused at the back of my case.
 
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fr0sst

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Aug 26, 2017
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I'd remove the motherboard and see if there's a rogue standoff underneath.

Like I said in my post I've disassembled the entire thing and checked everything for physical damage, there wasn't a rogue standoff either. It's really only the floppy cable; and my question is how far the damage (probably) extend, especially to the PSU.
 
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Globe221

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Jun 16, 2019
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Ouch! In my experience of putting things on the wrong way round and in the wrong place and causing smoking/fires (not in my PC - but product testing where I work) if things continue to smoke or burn then it is possible that the original excess that build up has reflowed some solder or cable insualtion causing a permanent short circuit. Given the tiny size of some motherboard components it might be small enough to go unnoticed or even hidden under the plastic header housing.

Hope you get it sorted (y)
 

fr0sst

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Aug 26, 2017
12
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4,510
Ouch! In my experience of putting things on the wrong way round and in the wrong place and causing smoking/fires (not in my PC - but product testing where I work) if things continue to smoke or burn then it is possible that the original excess that build up has reflowed some solder or cable insualtion causing a permanent short circuit. Given the tiny size of some motherboard components it might be small enough to go unnoticed or even hidden under the plastic header housing.

Hope you get it sorted (y)

Good one! Thanks a lot for the advice, I'll take a look.