iPhone7 will not start up after display replacement
So I do some word-of-mouth at-home phone repairs, and my latest repair has been the iPhone 7. I ordered the replacement screen, but I did have to transfer over things like the camera/sensors/top speaker, along with the home button, and the aluminium plate. Went well with no signs of any damage aside from having to cut something off to get the plate off (I hate Y000 screws so much!).
Plug everything back in (in the safest order), press the power button - nothing. Press the power button and volume down button for 10 seconds. Nothing.
The taptic engine does vibrate when I press the home button when I power the device on - this indicates to me the device is turned on. But the screen is still black. And the battery is charged - power readings show current went down to 0A.
Any clues on how I can get the device to start up?