Chosen Solution
The LED backlight on the LCD laptop screen is dark. I have researched dark screen enough that I am now sure the screen itself is functioning. I cannot find (and ACER is no help) any connection info (schematic,connector pinout,fuse location, or part layout) on how the motherboard feeds the backlight voltage to the screen. YouTube and manualslib.com were most helpful but not component detailed enough. All 7750 models similar in many respects. Asking because I’m cheap -retired, fixed income.
I’d say it’s the inverter… but LED screens don’t use an inverter. Have you double, triple checked the connections to the screen internally? Hopefully oldturkey has solved your problem… I don’t have the schematics myself, so I’m not sure what feeds the backlight on your computer. It’s possible a new screen would solve the problem $71 on eBay, and you can return it if it doesn’t work lol. Heres a new screen: http://www.ebay.com/itm/Acer-Aspire-7741… And here’s a new LCD cable: http://www.ebay.com/itm/Acer-Aspire-7750… Wish I could be of more help.
Attention ALL: This was my original question. I ended up putting it in the shop and the tech (from experience) tried everything I did EXCEPT he added one little thing. He pulled the battery maintaining the BIOS !!! He explained that if an upgrade had been done (it had), the BIOS would revert to a basic version without the cell. Long story short, IT Worked and the backlight started functioning again.
