I recently opened up my HP Pavillion dv5 1050ep laptop, to clean up dust and change thermal paste (laptop is 4 years old).
After putting it all back together, everything works except the display backlight. It simply doesn't turn ever on, no matter what.
I have already replaced the inverter with a brand new one to no avail.
I've done my best (this is an amateur best) to check that all cables were plugged in correctly, including checking the plastic connectors to see if all the wire were pushed in enough.
The only wire I found to be loose from its plastic connector was one of the 6 wires going into the connector that plugs the power jack into the motherboard. Even when the laptop was turning on perfectly with this one cable being loose, is it possible that this one cable powers the backlight? It is a red wire, left-most of the 6 going into the connector.
The only thing I have left to check is the backside of the display panel. Here I would find the end of the cable that plugs to the back of the LCD, and of course the backlight.
The reason I haven't opened up this part of the laptop is being very skeptical about having broken the backlight, or unplugged that cable on the back of the screen, by simply unscrewing and re-screwing the screws that secured the display assembly to the rest of the laptop.
Given the symptoms (display and laptop fully working, only problem being the dimness of the display), where do you think the pinched wire could be? The inverter to backlight cable seems in perfect condition.