Backlight issues here's how I fixed mine!
@John &Io Nut
I have an LED cinema display 24" from 2009, I have excatly the problem that the screen blanks out after a 1 sec flash of the image (probably LED driver signal turns down). I was about to try the bypass solution above for the 3.3V drive input, but then wanted to ask first if the same backlight strip probem problem could be on my LED Display as well, because I would not want to loose the dispay dimming possibility.
So I did take the LG LCD panel apart in search for the notorius LED Strip, see pictures:
Taking the LCD apart:
The LCD frame,
The Backlight panel,
The plastic frame,
The glass of the panel,
The back plate,
Finally getting down to the LED Strip
So I did resolder the LED connector (just added some solder to it and re-heated the 5 pins again thoroughly), but my problem still persists, the LED stripe only flashes quick at connection display port connection time. I am considering of doing some logic measurements tonight with my oscilloscope for the LED driver, but the willi fix for bypassing the 3.3V is starting to sound tempting (still trying to find out the real reason for this failure, and I have to admit that the LED stripe fault sounds more plausible to me due to the drive signal LED shutdown after one second flash.
I made some advancements with the display but the reason for the fault is still unclear.
All of a sudden the LEDs decided to turn on again.
I am convinced that it has something to do with the horizontal positioning of my setup. While lit I quickly checked the LEDs and realised that Led nr. 27,30,40 and 60 are out. Next day when I started the display the background lighting did not lit again.
I figured it might have something to do with grounding and tried out connecting the displayport without the USB cable. No effect the LEDs turn on with or without the other USB connector and/or the Powerconnector. I realised that the LED cinema display brightness can not be adjusted without the USB cable connected to the my macbook pro.
LED illumination pattern 2/3 Leds.
LED illumination pattern every third LED
So after all the MODs my display is running again. Eventually I ended up only changing 9 capacitors (3 pcs of each of the black ones in the pic, the orange ones I still have originals) on the powersupply,
and resoldering the LED stripe connector,
in addition I assembled and reassembled the display several times (loose connectors).
So Im still not convinced about the source of the fault and Im now testing the display for a week, lets see if it actually stays on.
My Apple LED Cinema Display 24" is still up and running.
Unfortunately I have to report that my LED cinema display died again after one month of fluent usage. So Im back to square zero. :!
I decided to try out if my display runs and it seems to run again :). So lets see for how long, but I am suspecting some sort of capacitor voltages that are incorrect due to capacitor ageing.