Original post by: io nut ,
With all due respect for the great investigative work done by Michael (and Willi) I have to admit that John the Aussie tech was right on the money with his answer. It appears the Thunderbolt Cinema 27" is affected by the same plague as the 27" Imac (2011), which is....(drum roll)...the LG display. Despite the fact that the iMac has CCFL backlight and the Cinema Thunderbolt 27 has LED bklt, the fault is exactly the same and in the same place: backlight connectors on LCD panel. Long story short: just finished spending 2 days on fixing the Cinema 27. 1- octopus cable damaged ------> replaced with new. Backlight still had a mind of its own (working whenever it felt like it) and eventually it stopped working altogether. 2- tried Michael's mod -----> backlight wouldn't still kick in at all, but the image on the lcd flickered 3- undone Michael's mod 4- remembered the iMac LG failure and took Aussie John's advice. Decided to bite the bullet and took the LCD panel apart. 5- re-soldered both backlight connectors on the LED strip 6- the Cinema Thunderbolt is back to life !!!! The job is extremely difficult (not for the faint of heart) and requires excellent skills (disassembly and soldering). Good luck everyone and thanks again to : John, Michael and Willi !!!