Hello! I got absolute identical situation, on same card.
Voltage of memory do not appears, an VCORE is about 0.9v.
This is my old broken videocard, Idk what happens with it, but I have no picture on screen and probably no voltage on VMEM could be a problem.
I will try to follow recomendations and resolder controller or electrical key that recommended to resolder e.t.c.
I still not found boardview for concretly this videocard, even in 2023.
If anyone have boardview for GV-N66TOC 2 or 3GD, please, help.
Thank you all for your help!