Tested an energised PCB, now not working (iPad)

[Brovashift]

Hi all,

Im looking for some help as Im a bit of a noobie when it comes to fault finding on PCBs.

I recently bought an old iPad off eBay that had lines across the screen. I like to take things apart and fix stuff so thought Id have a play.
In the past I have bought faulty electricals and took them apart, tested various parts for continuity with a small multimeter, and 9/10 manage to locate and repair the problem. Or sometimes simply give it a little wiggle. Job done!

So I've now taken the ipad apart and done various tests based on Google/YouTube tutorials but nothing worked. I decided to get the multimeter out to see if it would flag up anything, like a loose or faulty connection.
Everything seems to be fine, but now it wont turn on at all, and remembered after that I didn't turn the power off before testing the PCB components for continuity!

Would this have cooked something like a diode or something and so its next stop is looking like the bin... or might it be something less permanent like static, that could be saved somehow?

Any help appreciated, thanks.

 

[Georgy.Moshkin]

Maybe screen stopped working completely because of loosened connection or further damage. You can try to turn iPad on and then perform unlock sequence (with screen still completly black), if there is an unlock sound then main board is still working. Some older screens may have broken backlight, but you can still see something in the sunlight or with a flashlight pointing at the screen.