Original post by: pwvoogt ,
Same problems here with an Apple Cinema Display 24 inch. The problem of flickering and no backlight occurs mostly when the ACD is connected again to my Macbook 5.1 I developed a 'workaround' that's still working after 6 months. (I suppose the problem has to do with ageing capacitors, a phenomenon I recognize from audio electronics). The workaround is: discharge electric residue from all contacts of the display port plug of the ACD. First disconnect the ACD from mains, and disconnect the all-in-one cable from your Mac. Use a copper brush (like this one: http://www.tools.vocor.nl/data/articles/images/big/b_2136.jpg ) and place it carefully on the displayport plug while connecting ground (chassis) with all contacts. Then plugin the all-in-one cable to the Mac and after that attach the mains of the ACD (use a grounded connection). Sometimes I renewed the NVRAM and the SMC of the Macbook, before attaching the ACD again. Once in a while the backlight disappears for 0,5 seconds. An interruption that occurs less when you lower brightness. (Changing the logic board, like Roy Kenjataimu descibed in his comment, mostly implies also discharging electric residues.) I think an electric scheme is needed to search for an aged capacitor that might disrupt the proper working of the micro controller (as I suppose).