04-07-2023
VBAT and 3V3 rails in working condition, 5V outputs 0.2V
13-07-2023
tested a few times, working fine however the voltage lines incorrect
split moment, drawing too much current at an extremely low voltage, and smoke
gound and power are shorted
next steps: find the shorted component (the one that is smoking), use a thermal camera
15-07-2023
Need to order adapter for thermal camera
20-07-2023
tested impedance between components separating ground and power, seems to be none of components so far
thermal camera working, used to determine the zener diode between power and ground may be the problem
“Desolder the diode and see if the short goes away. Test the diode when its off the board (for both forward and reverse conduction).Forward conduction (as a diode normally should conduct), them diode should have a voltage drop about 0.6V. You can test this with the diode test mode on a multimeter.Reverse conduction can be tested with a power supply. Set a low current limit and start at a low voltage with the diode connected in reverse. Then start slowly increasing the voltage and see when the diode starts to conduct - make sure it matches the datasheet. Should be around 16V.Get a new diode as well and do the same tests and ensure that the values you get for that one are similar.“
23-07-2023
zener diode taken off, and the short stopped after removing
testing the diode for bias, seems like the diode was the problem
25-07-2023
controller board is not the problem, correctly outputs 3V3 (when testing independently)
when the controller board is connected and the PD is supplied with a 12V, the 3V3 voltage rail is supplied ~1.8-1.9V
when the controller board is connected, even the 3V3 rail on the CB is 1.8-1.9V