Hi there: I have a 15" Powerbook G4 that is about 4.5 years old. Last night the screen started to flash for about a second and then went to almost black. (there is a very very faint image remaining of the screen)... from surfing some forums, it sounds like this could have something to do with the backlight or the inverter (whatever that is?). The powerbook seems to be working fine otherwise, I was able to connect it to my 30" (which was amusing) to archive all data off of it, so nothing was lost. Techtool diagnostics all ran fine (nothing in there to repair a display). I suppose the basic question is if anyone knows much about what the problem is - and if its worth investigating repair vs just diving in and buying a new one... Thanks! some additional info found on Apples boards, but still curious if anyone has opinions/insight towards the cost and trouble of this repair: My screen looks black, but I can see very faint graphics on it Symptoms of this are a dark screen, but everything else seems to be running. If you get in close with a flashlight, you can usually see the image faintly. Backlight If your backlight isn't working, the inverter may be bad. Other parts that may be bad are the display or the logic board. If your backlight fails intermittently while moving the display, the problem is with the inverter cables. Otherwise it is impossible to test for damaged parts without replacing them one by one. If you are comfortable taking apart the display assembly, replace the display inverter first, then replace the LCD. If you are not comfortable with this, you can replace both parts at once by replacing the display assembly (which contains both components). If this still doesn't solve your problem, you need a new logic board.