Chosen Solution
I got hold of a iPhone 8 Plus with cracked screen that I am planning to fix. Already got all new part that I think I need. Here is my problem: When I tried to take out the screen from my phone, (step 15-18) I was curious about the new screen, so I tried to connect it. It was completely dead! Then I tried the old cracked one, and suddenly that was dead to! This is a phone that some fool has been inside earlier and changed battery in, but I suspect he has done some more really stupid things. The Taptic Engine is living its own life and vibrating every time I slightly touch the home button. (I have a new Taptic Engine) The phone is also full of dust and small particles that does not belong there. One tri-point Y000 screw (step 18) is even missing! Now the biggest problem is that both screens are pitch black! I know the phone is on, because I hear voice command speak when I turn on the power. What could this be? The screen worked before I tried to change it?!… And one last thing: My new LCD screen came with new flex cables. Is it possible to switch over, so I can use the old ones? Just in case that’s the problem..
There’s a lot wrong with this phone, more than you imagine. Here are my observations First of all, this is a water damaged device. You can see the red sticker in the top left corner.It also appears that some micro-soldering repairs (or at least an attempt) occurred because the CPU shield and SIM tray is missing the top sticker.As you noted, missing screws are signs that it was repaired. Losing an occasional screw is not a big deal, they are easy to lose. Whenever multiple screws are missing, it says that the technician was not very skilled.As for the screen, did you disconnect the battery before plugging in the new screen? If not, then you probably blew the backlight circuit, which is why the screen is dark.To test for this, plug your device into a charger or an iTunes enabled computer. Then shine a bright flashlight on the screen. If you can see a dim image, then the backlight circuit has been damaged. If you can’t see an image at all, then it may be the LCD circuit that is damaged.The constantly vibrating Taptic engine points to water damage on the logic board. This is more than a cracked screen device.As for the dust, that’s totally normal for an unsealed device, it’s amazing what can accumulate inside a phone, especially if the owner works or lives in a dirty environment.Your question about the flexes is unclear. The flexes are integral to the screen assembly. You cannot switch them over. *
