I have previously posted about my mid-2009 MBP which stopped working (no charging, no powering up). I have replaced the dc-in board and now the power adapter LED lights up and I can start up the computer shorting the power pads (power button doesn't work, probably something related to the keyboard cable?). When I short the power pads, the fan starts spinning and the front LED turns on, which means power is probably ok, but the screen remains off. I've tried connecting an external display, but still there's no signal. I was suspecting display cable, but I'm worried it could be something else since the external display doesn't work too. Any tips? Thanks.