Chosen Solution

Had to replace the graphic card because of stripes. After that the imac starts properly but without backlight. Everything works fine with an external display. 4 LEDs are on. Ive checked all connections already and replaced the the inverter power cable… without success. So, after reading the forum here, the most probably 3 faulty parts are:

  1. The inverter
  2. The CCFL Tubes
  3. Faulty Parts on the power supply Can somebody give me an advice how i can check each parts and sort it out? What are your experiences in those cases which part is more likely? Thank you! ;-) Update (02/10/2018) So… i got the donor LCD-Panel today… unfortunately the Display remains dark. :-/ So, i will check the power supply at next… Update (02/10/2018) After a little research… i think, THIS seems to be the more promising workaround: https://forums.macrumors.com/threads/ima…

If you can discern the desktop when it is on, replace the inverter, (it was a weak point on the 2007 model).