>>9180
Sorry, don't know what else to tell you. Sounds like you got power to the backlight at least. If it were me, I'd have it open and powered up, poking with a voltmeter and scope probes while looking at the schematic, working from the power supply to the processor. Unfortunately that's about all you can do at this stage, as more often than not parts will fail in ways invisible to the human eye, they're not all packed with liquid chemicals.
I'd say your next step is to either git gud with electronics plus buy that BASIC KIT that the other anon said would cost TEN WHOLE RUPLES in his country or, look for one with a broken screen or something to swap parts with, since it seems like you can at least take one apart and put it back together. Good luck.