Now I will ask the questions that have not been asked: What was plugged into the board? What external device was the 3.3V regulator powering?
As far as I can see in the schematic, there are no 3.3V powered components on the UNO board itself.
Now I will ask the questions that have not been asked: What was plugged into the board? What external device was the 3.3V regulator powering?
As far as I can see in the schematic, there are no 3.3V powered components on the UNO board itself.