Can I fix UNO broken while working on VIN?

Hi,

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?

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When I connect my UNO with USB cable it doesn't even appear in Device Manager. Power LED turns on and LED connected to pin 13 turns on too. The only thing I'm sure about it broken voltage regulator. I live in Poland.

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Does not appearing in Device Manager mean that USB converter is broken too?

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I probably did this:

Apply External Vin Power Backwards HOW Power your Arduino through the Vin connector pin, but reverse the polarity of the Vin/GND power connection. You will destroy several devices on the Arduino.

WHY There is no reverse-voltage protection on voltages applied to the Vin connector pin. Current will flow from the GND pin of the ATmega328P back up through the 5V pin, back through the 5V regulator and to Vin. The same thing will happen with the ATmega16U2 microcontroller. Both microcontrollers and the 5V regulator will be destroyed.

This may explain why UNO is not detected by PC and voltage regulator is broken.

Are you fixed your issue?

No. UNO is out of order. Not protecting VIN with diode while doing this for barrel connector for me seems to be feature, cause jurks will buy another UNO anyway and they will be able to sell more of them.

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