Question Soldering a new atx12v connector?

Sep 23, 2019
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Recently my PC has been cutting out where fans and rgb spin and light up but that's all it does. Usually a reset fixed it But last night it didn't. Upon disassembling my PC, I find that the blue atx12 p4 connector has been burned on one of the 12v rails and is likely the cause of the shutdowns since they started happening soon after I installed a new fan in my case, likely knocking the cable around into a bad spot.

If it's relevant, motherboard is a asus m5a78l-m/usb3 and PSU is a Rosewill Glacier 500w 80+ bronze.
It's also worth noting that part of the plastic on the PSU connector cable has broken/burned off inside the motherboard female port, relevant later.

Pics of burned connection:






I also have an ancient motherboard from an old Dell Dimension and was wondering if I could unsolder that atx12v plug and put it on my motherboard




I've checked for a PSU warranty but as I've built this rig about 4 years ago and I foolishly didn't keep any purchase records, none of the parts are under a warranty that I know of. I just want to know if I could remove the damaged plug, solder in the undamaged "fresh" plug, get a new PSU, and fire everything up as normal. Thank you all!
 
Maybe. But you might run into problems with multi-layer traces within the mobo or even right on the top where the socket would be covering the trace.

On the other hand, what have you got to lose? Well, a PSU if you get a direct short. Your choice.
 
The motherboard through-holes (via's) will be plated all the way through so you shouldn't have any great problem soldering the ground pins to the ground plane and the +12V pins to the 12V plane. Personally, I'd try to get hold of a brand new ATX12V connector to have the extra pin length which would make it easier. But in general it's very repairable if you're experienced at this sort of thing, and if you are experienced at it I'm sure you will take appropriate precautions before applying power.

But there's still the question of why the VRM was drawing such an enormous load to burn it out that way. Are you trying to run an 8 core FX heavily overclocked by any chance?
 
Last edited:
Sep 23, 2019
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The motherboard through-holes (via's) will be plated all the way through so you shouldn't have any great problem soldering the ground pins to the ground plane and the +12V pins to the 12V plane. Personally, I'd try to get hold of a brand new ATX12V connector to have the extra pin length which would make it easier. But in general it's very repairable if you're experienced at this sort of thing, and if you are experienced at it I'm sure you will take appropriate precautions before applying power.

But there's still the question of why the VRM was drawing such an enormous load to burn it out that way. Are you trying to run an 8 core FX heavily overclocked by any chance?
FX-8350, but its running at stock 4GHz, voltage set to auto in bios. I may bump clock down to 3.8 or so. I also chopped up an old Northbridge heatsink and thermal glued it to my vrms to help cool them. I dont think its an overdraw problem so much as an inconvenient bump loosening the connection. CPU ran fine for the past half year or so. Thanks for the rest of the tips though!

Edit: you can see parts of the heatsink in the pictures, 6 black prongs
 

BFG-9000

Distinguished
Assuming everything is still working, I would just solder the wires directly to the board--why waste a PSU? Later on, if I ever wanted to change the PSU, I'd crimp a P4 2x2-pin extender cable to those wires so the new PSU's cable could plug right in. If you prefer to change the PSU right now then yes, replacing the connector works too and keeps the stock appearance.

Those connectors are rated for a surprisingly low number of mating connections--even Molex, who invented that type of connector and is considered top quality, rates theirs for only 30 insertions before the plating wears through. Whether worn plating or looseness (there is after all a tolerance they are built to) or corrosion or even dirt, resistance causes heat and when it gets bad enough it will burn.

The FX-8350's 125w really isn't too much for a 4-pin as each pair is supposed to be good for 10A. Theoretically it could even support a 220w FX-9590.
 

sjozsika11

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Jul 29, 2020
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I had the same issue with the same board, but my CPU is Phenom II X6 1055T. First when the connector burnt, I thought it was the PSU, so I bought a new one. But I can see that its connector starts burning again. System is still working though sometimes it just freezes or restarts. Now I plan to build a whole new system, it's too old anyway.
 

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