Xperia Z4 tablet - SGP771 - won't start, just blank screen

[htohlsen]

I have had my tablet lying turned off for over a year, because the battery couldn't handle being charged all the time. I now have had a new battery put into it, but all that happens when I start it is that the screen kind of comes on, absolutely nothing else. Does Android get deleted from an EEPROM or something what the tablet is left turned off and no power on the battery for a longer time?

How do I get Android back onto the tablet so it'll start again? I have tried attaching it to a laptop to see if the Xperia companion reacts, but no reaction at all.

[Strampke]

First be shure the new battery is charged.

Then turn off you tablet.

Start Xperia Companion and tick on 'My device is not recognised or is a smartphone'

Then follow the instructions.

Hope you'll get it right.

[Lord_viridis]

I would check that the person that changed the battery has connected the 2 display connectors correctly.

The backlight could be on but the display shows no actual image is common with a bad display connection.

[Piscie]

Hey @htohlsen, has it been repaired at the Sony authosied service centre? Also, keep us updated with the software repair outcome!