A few days ago I bought a ST7920 128x64 screen (http://www.allshore.com/pdf/Sitronix_ST7920V33.pdf http://www.satistronics.com/myfiles/file/LCD/YB12864ZB.pdf
), Arduino compatible. I've got all the libraries and stuff, everything works correctly on my computer, but when I tried it with Arduino, there was motion (it was supposed to be), but it was kind of messy. I tried connecting it both in parallel and serial, but I only could make it "work" in parallel mode. Afterwards, I looked more carefully at the datasheet, and found the Reset pin, that I had left unconnected. I put it to GND, since it's the value it is supposed to have, but then I put it into 5V, trying to make the screen reset. The problem was that since that moment, the screen doesn't work anymore.
If I've broken somthing, could it have been a fuse? Maybe with a steady hand I could resolder a new one again...