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“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 (with test points both on the pd and cb)
it was suspected it may be the CB connector, however, the 3V3 on the CB is also affected when testing
01-08-2023
The pins of the connector do not look properly connected, so resoldered a new connector to the PD board
Tested all the pins for shorts, seem to be all properly connected
Checked ground and power for shorts, high resistivity > not shorted
With a PSU, 12V was supplied to the board with the CB connected
Proper 12V at input wires, and the 3V3 correctly outputs ~3.3V at multiple points on the board
5V buck converted outputs ~5.5V
Input power supply: 12V, 0.042A