To check the U10's function, you will need a multimeter. You'll need to ensure that the 3 GND pins are all connected to GND, pin 5 is being fed 3.3v, and pin 4 is outputting between 2.6v and 3.3v.
If one of the 3 GND legs broke off, you'll have to use the U9 instead. If connection to GND or...