3.3V interface on arduino is only giving 0.23V
The first thing to verify is the 3v3 regulator, you could start measuring voltages at the IC6 pins (3v3 regulator). Connect the negative probe of a multimeter to ground. Put the positive (red) probe in the IC6 pins. There should read 0V at pin 2, 5V at pin 1 and pin 3, and 3v3 at pin 5.