ASUS ROG MAXIMUS PQ301 gets hot

[iblackford]

Hi all,

I have two slightly different (but I'm sure similar...) ASUS ROG motherboards that have essentially the same fault. They are the ASUS MAXIMUS VI GENE and the ASUS MAXIMUS VIII HERO. Both have excessive loading on the +3VSB rail, which makes PQ301 get very hot. I did some searching through the forums, and it looks like someone had another ASUS motherboard with the same fault, but there was no follow-up on what eventually fixed it. I feel like it should be a common issue, but I don't know. Does anyone have any insight on what components are most likely at fault? Does anyone have a schematic for either of these two boards?

Any help it greatly appreciated,
Thanks, Ivan

[DynaxSC]

Most probably your chipset is dead and has a short. You can try to inject voltage from an external steplessly regulated power supply with at least 10A current output behind the PQ301. Set the voltage eg to 1-2V, and increase the current limiter from 0 in 0.5 A steps until you can identify a hot spot. Take off the chipset cooler for this. To better find the hotspot you can spray isopropylic alcohol on the board. It will vaporize in the hot spot. Inner side of the hand is also a good temperature sensor (attach it to the buttom side of the board to first find the approximate hot spot area location), as well as the finger tip for the precise location. But pay attention not to burn your finger , tap the finger tip first time on the chips only very short. To make the shorted chipset hot often several amperes are necessary, as they usually make a very low ohms short. A thermal camera this would be the most convenient solution, but they are quite expensive.