Bought another Macbook for project. Very clean externally but cannot get chime or video. LED is constantly on. I removed memory sticks and they are oxidized as far as I can tell, contacts were covered in white powder-like substance. I tried cleaning by using the tools I had which means that I have no tools designed for the job, it made no difference. The machine reacts to PMU reset, the led flickers rapidly and then stays on, normally it would go off and the booting would begin. The computer also seems to be display some kind of error message when there is no memory at all, the led flickers in pattern. Does this sound like memory slots need better cleaning or is it GPU problem? I'm considering buying oxidiation cleaning liquid (sorry I don't know what it is called in english) and trying with that. I have also ordered tools for GPU reflow before this project so I could also try that when those tools arrive. Tips are appreciated. EDIT: I think this is Core / Core 2 Duo -model so it has Intel graphics which don't fail that often. I'm currently away from the machine so I cannot check, but it is definitely older machine so GMA 950 or X3100 inside.