I am running into the issue of getting the undervoltage detection on my Pi 3 B V1.2 while it is connected to an original psu (which provides 5.1V/2.5A).
The psu definetly works as intended (I tested it with watt meter and other Pi's of the same and different model).
I measured some voltages on the board and
- confirmed that 5.15 V are applied on the USB connector pins - measured with PP1 and PP5 (See figure down below) . Same goes for C5.
- found out that the voltage between PP7 and PP5 is only 4.5V, hence the undervoltage trigger is justified.
During these measurements the Pi was running an idle Octoprint server and consuming about 1.25 W. So I wouldn't assume that some consumer on the board is e.g. shorted and dropping the supply voltage.
My guess is that something in this black square is broken, but I am not quite sure on how to troubleshoot this. Did someone already encounter such a problem? Any help is gladly appreciated. Thanks everyone. :)