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I have attempted a repair on an iPad Air with a cracked screen. Prior to starting the repair, the iPad worked with the cracked screen. After the repair, which went flawlessly, the iPad would not turn on. If I connect the iPad to iTunes, iTunes recognises the iPad but says that the iPad is locked and must be unlocked before doing anything else. At this point, I assumed I had purchased a dud digitizer on eBay and ordered a new one from ifixit. That arrived this morning and I repeated the repair procedure… with the same result. At this point, I am assuming that I must have somehow damaged the LCD screen during the repair. Before I go ahead an order an LCD screen though, I would like to know: is that a reasonable assumption?are there any tests I could perform to confirm this diagnosis? Thanks…. Steve
At the suggestion of Mike from iFixit, I disconnected the battery from the logic board and then reconnected it. After connecting the power cable, the iPad Air booted up, screen working fine. Hurray! Unfortunately I failed to check everything before sealing the digitizer back on and failed to notice that the power button and magnetic shut-off is not working. Back to the drawing board.
Hello Steve Song, it seems to be you are in trouble now, Step 1 Replace old damaged screen and check whether functionality of device. if it works fine no need to touch logic board. Step 2 logic board detecting by the iTunes means power and processing functionalities works fine and you need to focus on visual output, check any sign of damages in Display connector, any burn marks or can you observe any component missing on logic board? Step 3 if you plug bad quality LCD such as back light short circuit LCD, back light driver getting damaged. i guess what you experiencing new, so you need to troubleshoot stating from coils, Check Display Drive instructors (Coil) 4R7 : if defective replace itCheck the diode near 4R7 : if defective replace itCheck the filtering cap (Down side of diode) : if defective replace it Hope this will be help you to bring back display. Good luck!
