Hello I am new in this area, I am building a small project where I use mega 2560, ultrasonic sensor, and H. Bridge Yesterday I had a little incident where H was the bridge connecting the arduino, which was connected to the notebook I use. After making the connections I saw that the arduino did not have enough power to put the engines to work completely, and I remembered that I had saved one of those motorcycle battery, 12v 7amp, and called the H-bridge and the engine, which was followed a scheme. So that by my carelessness, nor cared polarities, and when I turned on the second wire in the engine, immediately saw that my laptop is turned off, the arduino started making a noise like a hiss, immediately removed the battery. I move around in one notebook and everything is normal, so that my arduino is a bit strange when he plugo the notebook, he turns on the light power that is always red, and the second LED 13 blinks once and goes out. And after the notebook identifies the Arduino as a USB device not recognized. Where tried in many ways it reinstall the drivers, but without success, because after the error message 10-The device can not start. If someone went through this and could give me a hand because I am a project due date, and I'm tight with time, and wanted to save money because they do not intend to buy a new arduino. Thank you for your attention.
I think you are out of luck there. Sounds like you damaged the USB/Serial interface part of the mega at least, and maybe more. They are not user-friendly to make repairs on without special equipment.
Doesn't sound good.
Based on the blinking pin 13, it sounds like the 2560 may have survived but the USB->Serial chip sounds like its gone.
On the Uno and 2560, I believe that they use a 8U2 microcontroller. This is a surface mount device with tiny pin spacing (worse then an FTDI chip which is hard enough). You would need highly specialized surface mount equipment to change it.