Have you got an oscilloscope?
I'd look at the inductor waveforms, and then the gates on all the mosfets.
See if there's a gate resistor that's cracked, or open.
The 4 phases on that chip should be 90 degrees from each other, and it uses 2 mosfets per phase, but the 4 mosfets on the lower side won't run as hot, IMHO.
See how the mosfets are connected to the chip on P23 of the PDF file above.
Half the mosfets being cool may not be an issue; on the P5wd2 premium I'm working on, the lower mosfets aren't heatsinked, but I'm adding small ones.
If you hit the current limit for the switching, it will turn off the phase early; you can go too much capacitance.
Take a look at Table 10 in the pdf; see what kind of current limit it's running.
If the cables get hot from the PSU, you can buy pins and wire and make your own cables; they have pins that handle 16AWG wire, but each pin is only rated 9A.
That's why there are multiple wires per voltage. Most PSU's use 18awg cable.
Solder another connector on the bottom of the board, on a short pigtail, if you need more current than the pins can handle.
Here's a link to all the different power supply cables, pinouts, ans Pin numbers:
All about the various PC power supply cables and connectors
All about the various PC power supply cables and connectorswww.playtool.com
These pins are for 16awg wire:
Molex 39-00-0168 Fem WM3115-ND at digikey
Yes, I have a scopemeter. I will attach it sometime time during the week to see if all is ok. It can also be a faulty controller which I was not aware of as I got the motherboard off Ebay 2 years ago. I have spare controllers here if I need to change it.
The motherboard was operating more or less the same before i changed the MOSFETS, this why i think it's a controller fault.
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