I've attempted to fit a A1286 2.66Ghz T9550 Early 2009 Logic board into my 2008 Unibody A1286 2.4Ghz 15" Macbook Pro. The...

The buttons on the TV failed, check the controls on the actual TV. You will need to open up the TV and pull out the button control PCB board and disconnect the wire harness connector from the board. The TV is easy to open, use a Philips screwdriver and open about 3 quarters the side where the controls are, you do not require to disassemble the entire unit, just enough to remove the button control PCB board. The TV should work without the “This function is not available now" error. If you don't use those buttons(you have a remote), you do not need to replace the button PCB board.

Upgrade to an SSD of capacity above 500gb and swap out the optical drive for additional storage with an optical expansion bay(opti bay). A 2009 MacBook is still very useable today. The SSD would increase the usable speed, in fact, the mechanical HDD is a relic compared to every other component in the computer. You will not regret it! i would also check if OWC has a memory upgrade beyond 8GB, I recall the 2009s could do 12gb but I could be wrong.

Incorrect BinaryHaze, A1286 MacBooks run an LED backlight configuration without an Inverter. Sounds more like a connection LVDS problem or a shorted backlight.