Aporte original por: originalmachead ,
'''Connect to an external monitor'''... if there's no image there when the on-board display is black it's your GPU/VGC, however if the external monitor looks fine when the display is black it's your on-board display chain... possibly your inverter or display itself. Run your Apple Hardware test - you may have to run it more than once if your problem is intermittent. The diagnostic LED lights can also point to a problem area. ''If this answer is acceptable '''please remember to return and mark it'''.''