recently I broke my UNO while working on 8.5V VIN from 18650 connected via charger and step up converter. Now when I connect my UNO to PC via USB cable, PC doesn't recognize it. On 3.3V power pin 5V is present. I've checked voltage regulator with multimeter and it outputs the same voltage it receives on input (GND and OUT of vr are shortened). Power LED on UNO is on. Can I repair my UNO by just replacing broken voltage regulator or some other parts need to be replaced too? Maybe it's not worth repairing at all?