One of my EM3 has constantly shown 0 V and 0 A even I have given some real loads to measure but nothing has helped. Swapping it out solved the problem.
Now I have almost working device on my hands. Are there any HW debugging hints like what signals test points are and how to power up them safely? I don't want to give full reverse engineering treatment to it just to fix it.
My guess is ADC power or communication between ESP and ADC
I'll fix this if the problem is simple and easy and throw away if it doesn't solve poking with multimeter, scope and soldering iron.