If it worked fine for two weeks and you haven't dropped it or got it wet, most likely the ear speaker, shown in the picture above, is not aligned with the front camera and sensor flex cable. You should be able to get it working by re-aligning the ear speaker with the gold contact points on the flex, and make sure you put the correct screws holding down the ear speaker bracket to secure the ear speaker down properly so it doesn't move. Alternatively if it does not work, it may be possible that either the ear speaker itself, or the front camera and sensor flex wen't bad. However, these parts don't go bad "just because"
Rubbing alcohol can be made from isopropyl alcohol or surgical spirits. I would not use rubbing alcohol because you can't be too sure of what is mixed in or even isopropyl found at regular stores due to the pureness of the alcohol. You should get 99% pure isopropyl alcohol to be safe when cleaning your logic board. You can find it at most electronics store, it's not expensive.
As stated above by L Pfaff, you should definitely clean the logic board, especially around the battery connector, with Isopropyl Alcohol. Percentage not updating can be cause by a faulty battery, but more than likely it's a capacitor next to the battery connector that got damaged. In your case, you probably just need to have the shorted component replaced. You will need a micro soldering expert.
Can't be sure without thorough inspection under microscope. However, your issue is most likely related to IC responsible for your touch. The issue is very common in the newer iPhones, but can still affect older ones depending on impact or water damage. In some cases the actual connector may have issues as well, this should be easily able to be seen with a lit magnifying glass if you don't have a microscope available. Both issues are repairable but may not be worth it for those devices.
If you are stuck on Apple Boot Screen and if the actual Home Button now works follow these instructions; (All data will be erased, but at least the phone will work) (1) 1. Open iTunes on your computer, plug the Lightning Cable to the USB port in the computer and leave ready for connection to the iPhone. (2) 2. Press and Hold the Power Button and the Home Button at the same time, until the screen goes black, then let go of both. # 3. Once the phone is off. Hold the Home Button and plug the charging cable in to the phone. Do not let go of the home button until you see the iTunes logo, you will also hear the computer detect the phone. # 4. In iTunes, click Restore or Restore and Update, depending on what pops up. After it finishes the restoration, the iPhone will be on a white "Hello" welcome screen. Now you can use the phone as normal.
The phone will work without the front camera flex connected. However, be aware that your voice dictation mic (siri mic), proximity sensor and earpiece speaker (not loud speaker) will not work. Is there an issue with the front camera?
I would try to soft reset the phone by holding home and power button at the same time for 30 seconds with the new screen on. If you still have no picture with the new screen but you have picture with the old screen, then you have a hardware defect. You need a new screen. Try to get an OEM like replacement, some of the chinese LCDs can cause issues.
If you unplug the new home button and use a known good home button you can get the phone to power back on by unplugging the battery for a few seconds, plugging back up and use the home and power button together to get the screen on. The issue is within the new home button itself. It shorts the phone and the phone goes off and won't come back on. Usually doesn't cause any actual issues, it is just how the phone reacts to the home button. It is probably too late for that button, you will need to get another one. Make sure the phone and screen are on when you plug in the new home button, at that point the button will work.
Hello, If the issue was not present before the charging port replacement, then the sudden loss of signal is most definitely stemming from the replacement. As always, before proceeding always make sure to soft reset the phone by holding home and power button simultaneously for 30 seconds. If problem is still present, try steps below. 1. You should check under the battery connector cover, if the gold antenna connector isn't plugged in, plug it in. 2. If the connector is plugged in, you need another charging port. Charge port issues, while rare, still occur. Sometimes the solder from the antenna connector on the charge port is loose, or improperly done. A new charging port should fix the issue.