Computer does not detect Arduino uno.

Hi.

My pc can no longer see my Arduino uno.

It happened after i tried to make a stepper motor work. I was using a motor shield but was using a 12v adapter to power the whole thing through the DC barrel of the arduino board (i know i should have provided power to the shield directly but wanted to try something real quick).
The board was plugged in as well to the pc

The motor was rocking back and forth so i decided to provide some resistance by holding it which, i believe increased the current draw. Then i saw a light whitish smoke coming from the arduino board just behind the DC jack.

Disconnected immediately and something was warm there.

Now when i power (both through usb or dc jack) the board TX and RX led stays on together with the L led.
The arduino executes the previous program loaded onto it without any issue.

I have been digging around most results says something about the polyfuse or the voltage regulator but the board works fine so those are the unlikely problems.

Can i salvage that board ?

I don't think you will ever be able to use that board again.
Since you said that both the RX and TX lights are on makes me also believe that you broke the USB to Serial chip.
So you will probably have to replace that chip and i don't think you can buy just 1 chip.
So i would recommend salvaging parts of that board that are worth keeping for future use and just buy a new board.

Yes, you can buy just 1 chip
https://www.digikey.com/product-detail/en/microchip-technology/ATMEGA16U2-MU/ATMEGA16U2-MU-ND/2050821
Getting it off and a new one one will require a hot air rework station, and then it needs to reprogrammed.

Salvaging parts off the board is also easiest done with a hot air rework station.

Next time, don't move wires around when power is applied.

I think it is easier if i buy a new board and salvage parts from that one.

Thank you for the insights.

Can a surface mount chip changed by the average user?