Any chance of identifying how this GTX1070 blew a mosfet/VIA on the PCB?
The circuit in question is the NV12V circuit on the PCB.
I've concluded that a short occured within the multi layer PCB on the NV12V circuit after Q521 between R931 and R938, possibly in the vicinity of the plated via.
This short, initially blew out the Q521 MOSFET as it was likely only rated to 115mA. Once replaced, Q521 was able to supply up to 300mA which once powered again supplied enough power to blow out the plated via on the PCB. Either way, there was still a short.
I've drilled the plated via out and the short remains and so seeing only R931 and R938 remain, desoldered their resistors and replaced them with others overboard directly to the remaining NV12V circuit.
The card lives! Albeit the HDMI isn't detected, the DVI is and that's enough for now.