I have an arduino UNO R3 and I was trying to make a laser engraver from cd-rom spare parts, as I read at instructables site (if there is not problem, I can upload the link of the constraction's topic).
But something went wrong at the constraction of the laser drive circuit and it seems it ruined up the arduino. I was using the same ground and power for the whole circuits, for arduino and the laser driver too.
But I did a big mistake that I realized it too late, I had connect the negative output of the laser driver at the common earth, so after a while, as I was trying to upload something at arduino, it became really hot and then the pc turned off. Then I removed arduino and left it to become cold, I turned on my pc again and I tried one more time, but this time arduino was not communicate anymore with the pc and it was becoming hot very fast.
I forgot to tell you that the only part that becomes hot is the lmv358 into 10-15 seconds, that you can't touch it at all, without any load or connected devices at arduino. The arduino seems to start working when you plug in the power socket, the "on" led becomes green and the "L" led blinks for some times, then stops and then it is doing one blink and turn off again. When you push the reset button it happens the same, so does this mean that Atmega328 is working finally?
I am using an external power supply at 12 volts.
Do you have any idea about how to fix this problem? If I change the lmv358, will this make my arduino back to life again or it is more complicated?
I can change it, smd is not problem for me, but I will need your help to determine where is the exact problem, as it might be another component that cause this problem.
I don't know where to start and what to measure to find the problem, so if you drive me about what to measure, I can tell you the results and maybe we can find the faulty parts.
Do you think also that the atmegaU16 might be dead? Is there any way to check this?
And something last.. Nice to meet you guys!