shows some light but no video

Connect to an external monitor. If you see the same thing you have a VGU/VGC card problem and replacing the logic board would be the fix.. If the external monitor looks normal your problem could be the LVDS Display Cable, or the display.

Running AHT and observing the results off the working external monitor might point to the problem.

If you have dropped the machine, or been inside it, you might have loosened or damaged the cable.

If the problem is not the VGU replacing the cable would be a cheap place to start. It is an advanced DIY project - obtain the proper tools (every job is easier when you use the right tools)... STUDY the guide before you begin (most problems from complex repairs come from ripping a connector off the logic board because they were pulled the wrong way, or not unlocked before removing). Keep all screws separate and identified for easier reassembly.

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