Chosen Solution
I have just replaced the rear camera on my phone. Having turned it on, the phone is now almost unusable as any kind of touch movement I do is laggy, freezes and sometimes does not respond at all. Along with that, while the phone is being used, it restarts at random. Prior to doing so the screen’s colors will distort or gray out. The phone also no longer updates the battery % (for example will show 100% until it manually restarts) , takes longer than usual to read SIM card, the home button seems to fail sometimes. This is quite serious yet I don’t see what could have gone terribly wrong when replacing the camera for this to happen, not to mention I’ve teared the phone apart various times with no problem. I only forgot to unplug the battery before the screen and one time unplugged the battery while the phone was on (the power button stopped working and there I was stupid for not remembering that can also be done with assistive touch). Any leads on the cause for this? Edit: Having once restarted the phone myself, it then did so on its own 4 times within about 6 minutes of usage and then no longer restarted. Could mean there’s a pattern to the restarts. Edit 2: Resetting phone settings solved the freezing problem. For a while the restarting went volatile, happening every 3 minutes but now seems to have stopped. Shutting the phone off and on manually seems to trigger a restarting spree. I don’t really need to turn off the phone, so I’ll just stick with this for now. I think there’s some hardware problem as I’ve tried pretty much anything that you can do to stop these kinds of restarts and it was to no avail.
Unplugging the battery shouldn’t cause any issues as I’ve done this a lot when needed. Did you at least unplug the battery when replugging back the screen? This part is crucial as it’s bad practice to not unplug the battery before unplugging anything else in the phone. Try reseating the front display connectors. Do you remember if you put the 3 screws for the front display metal plate in the exact correct spots? Putting the demagnetized one in the lower two can cause damage to the logic board circuit cutting one of the circuits which can cause this effect on the display. Check if you can see copper or golden stuff on the screws itself, if it is then you have probably broken the circuit tracking like I said above. It is fixable by doing some careful soldering but I’m not really sure how it’s done but I know there are people that can do it and are experienced at fixing this problem. In the end it could just be a screen that has just gone unfortunately bad after disassembling phone. Could also be the ribbon connector pins on the logic board for the LCD display being damaged (it’s the one with the smallest amount of pins from the other two connectors which are for digitizer / touch screen ribbon connector or front camera ribbon connector.)
If iPhone have not response but can be connected to the computer, then there are a lot of software can help to fix your iPhone. And if your iPhone have response for tapping on the screen, then there are many manually ways to fix it. I have read an article about how to fix freeze iPhone, i think this is a little the same as the problem of screen black, the articles introduce several methods to fix frozen iPhone, you can check and have a try!
