Periodic black horizontal Lines / dimming on two thirds of screen
I am currently working on replacing a digitizer with broken glass with a new one on an iPad Air 2 32GB WiFi, so far the progress has been great.
Using heat I got the display assembly off of the device unharmed, I then seperated the old digitizer and the LCD with cutting wire, and ended up carefully cleaning the LCD with acetone to get rid of the clear adhesive. In the end I had a perfectly functional LCD, that was waiting for a new digitizer to be glued on.
I am not sure when it started happening, but recently the LCD started making these grey regions two-thrids across the screen that also flicker and vary in intensity. (see Picture, the line goes across where the two arrows point, everything from there on above is grey/darker as the bottom).
Then, without touching, these grey areas go away, only to come back every now and then:
At first I thought I had ruined my LCD during repair, however I dont recall knocking it over or cracking it somehow, and I checked the flex cable and tried tapping around the LCD or other components to see if a loose connection would fix/show any change.
Since these lines to flicker sometimes, and in the next moment disappear completely, I cant seem to figure out whats wrong. I did notice that these lines usually disappear after using the ipad for a short while, but immediately after locking and then turning the screen back on, these lines appear.
I have already tried a hard reset and restore. The LCD looks just fine sometimes, but I want to fix the issue for sure. Because these lines appear and go away with no apparent reasoning I believe it might be a cold solder joint on the main CPU/GPU, but I wanted to hear your thoughts first. It wouldnt make sense to glue on the new Digitizer just yet when the fix for the issue would involve the need for access to the front side of the LCD.
If needed I can provide further details, Id be glad if anyone has any ideas or suggestions!
And as usual, thanks in advance!
Ist dies eine gute Frage?