Sometimes devices can take up to 2 hours on charge to turn back on. If this does not do the trick then try the following: Press and hold both the Top button and the Home button for at least 10 seconds, until you see the Apple logo. If this also does not help then your battery is more than likely bad and in need of replacing. If you have an amp meter that you can plug a charger into then you can at least test to see if it’s drawing amps. This should help diagnose the issue. Amp/Voltage testers are really inexpensive on places like eBay. Also on iPods it is common for the power buttons to become damaged and unusable. Good luck!
You need to remove the battery ASAP. I cannot recall off the top of my head how hard the s6 battery is to remove, but the s7 is a difficult removal job, so the s6 will be about the same difficulty level. If you are not confident in removing it without further damage then take it to a reputable repair shop and have them do it for you. The costs should be minimal compared to other types of repairs… Samsung Galaxy S6 Battery Replacement DO NOT USE THE PHONE IF IT STILL TURNS ON AS YOU COULD HAVE A FIRE START! Good luck!
Try booting your phone without the charging port connected, you do not need to remove the charging port, just unclip it from the board and then boot the phone. See if the problem persists, if it doesn't then the new charger flex is damaged. It's quite common for new charger flex to sometimes not fully work. We make a habit of ordering 2 charger flex for our iPhone repairs for this very reason. If the problem is still occurring after disconnecting the charger flex then yes there is probably a logic board issue :( Good Luck :)
If the phone has not been dropped or suffered shock damage it may be worth trying the following: (1) Use the Power button and Volume Down button. (2) Press and hold those two buttons for a couple of seconds. Usually, it takes around 7 seconds or more before it works. (3) The phone will go off and reboot. You can release both buttons and wait for the phone to reboot and start operating again. Good luck :)
Yes, you can swap the motherboards, but, be aware that a lot of features will disable due to apple part pairing with the logic board. You gonna lose True Tone, Battery Health Reporting, Touch ID, etc. The list is off the top of my head, but you will have less functionality from the phone. If you do not need or require these features then you might as well swap them over :)
I am certain that your battery is in poor health and will need replacing. You can either take it to a reputable repair shop and have them do the repair, or, it seems simple enough that you could possibly buy the new battery and fit it yourself :) Nextbook NXA116QC164 Display Assembly Replacement
The easiest way would be to buy a little USB Amp/Volt Meter and plug it into the wall and then your charger cable into that and it will let you know if the charger is drawing amps or not. If not it’s most likely in need of being replaced. The meters are less than £5 if you look around…
It’s possible when you lifted your screen you caused damage to the flex cables or LCD itself. As iPhone 7 screens are relatively expensive I would advise buying one and fitting it without the home button and see if the apple logo shows. Then you will know for sure if it’s the screen or logic board damage.
Touch ID is one of the hardest things to restore. I am not sure about iPads but there are programming tools such as the JCID that can copy the codes that pair your button to the logic board, then write them to a new home button. This should do the trick in getting a replacement home button’s full functionality back. Most components in apple products are paired with the logic board and either stop working or disable features after the pair component is changed. Again there are programming tools, I use the JC V1S myself on iPhone repairs, but I have not looked into iPad programmers. Hope this helps :)
Sound like you accidentally, or the iPhone has booted into DFU mode, which is usually a black screen and only shows on the PC. Try holding the home button and power button for up to 30 seconds, you might get an apple logo. If this doesn’t work and you have no data to lose, try using 3uTools to flash the device with the latest iOS. I had 3uTools get iPhones to flash and boot when iTunes couldn't. Hope this helped…