Chosen Solution
Ok, so I replaced the screen on an ipad. (PROBABLY the 500 I have done) Here is the issue. When I unplug the battery and and plug it back in the ipad will power on and show the apple logo. As soon as the apple logo goes away the ipad screen goes black. and if I press the power button it will not wake up, but if I hold the power button the screen will come on with the slide to power off sign. Does anyone know what this could be?
Okay so the issue you are having is due to the small component chip on the home button cable which is used for the smart cover sensor. Also a partially ripped / damaged home button cable can cause this too. A bandaid fix is to go to Settings > General > Smart Cover auto-lock disabled. (Or something named like that). Then you can use the lock button as intended normally but smart covers will not auto-lock / switch off screen when closed. I think the replacement screen home button cable is missing the components on it. Compare it to the old digitizer home button assembly and you may see that it has components that needs to be transferred (via microsoldering) to the new digitizer assembly home button cable. Those components are needed for smart cover lock to work properly and also fixes lock button issue.
