Dear all! I'm very happy i have fixed my 3rd generation kindle after a lot of work. I'll list the things I did, although I can't guarantee the order the it took place in making it working again, or even if they were all really necessary.. however it's fixed!
First the biggest symptom: my kindle won't charge. When I plug it to charge, the orange light comes up for a few seconds and then turn off, without changing the screen. Hours and hours plugged in have not worked, always the same with the orange light on for a few seconds then off. My first conclusion was the battery has gone. I bought a new one, and opened my kindle for the first time in life to change it. For my misfortune even after it the problem still.
I must have opened my kindle 3x times after that trying to find something I did wrong. With no explanation it got back working in one of these times, but after a few days without use the problem returned. Today, after taking a lot of attention to the insider mechanisms of the slider which we use to turn on, I noted there was a chip (like a little processor chip) that was not placed well. Looking your kindle from the backside, it's in the bottom left, just a bit up and left from the on/off slider. There is a golden flat cable very near the place we force to open the kindle background. This flat cable plugs to this "processor" and this piece was loose. I just pressed it, headed a click, and noticed that my kindle got on! :))))
So as another colleagues have said it seems kindle do a test when getting on and if anything is wrong it goes off. So if you are facing this issue, check with a lot of attention each part of it after opening. Any loose or damaged piece, anything that seems to be wrong cause probable this is the reason. Of course I'm not sure with my original battery was another part of the problem and really needed to be changed, and I'm not in the mood to change it again to check kkkk.. anyway, I hope my story can help anyone with this problem to reach the solution!! Cheers!!