Chosen Solution
My iPhone 6 was damaged badly so I replaced the screen and moved the logic board to the same model housing of a different phone that was icloud locked.and it turned on. Then I decided to replace the battery and it also worked. I left it connected to my computer for about a day or two because i just forgot about it and then it doesnt want to boot anymore. So i bought a new battery and it still wont turn on and the battery is working because i tested it on another phone. Now my phone doesnt boot at all and doesnt connect to itunes or anything.
There are two possibilities here: You may have damaged something when you transferred over the logic board and screen. Double check your work by following these guides.If the original phone was badly damaged, it probably had some effect on the logic board. Moving it to new housing only moves that problem over. What kind of damage did the phone sustain? Was the housing bent or mangled? Because that can cause issue on the logic board at the trace and solder connection level. The board may be repairable but it would require a micro-soldering repair.
