Welp. I am going to toss out a random idea. You may try it if you like.
Open it up to the screen. Wipe the clear screen off. Make it so you can see out of it. (that was the easy step...)
Now, Try to run a q-tip around everywhere you can see the black. Even the lump of black too. (You may need to repeat this)
With your eyes (Or microscope if you randomly have one you can use/have access to) Look to see if there are any holes remaining with the black still comming out or "Stuck" black anywhere.
If so... this is the one that will be a chance........ Squeeze the circuit board/visual inner screen display to see if more comes out. If stuff comes out, or it raises even a tiny bit... you get lucky because you can see it come out. This fix, Dab of super glue. Let it dry. Add more glue after more drying. Very important. after you are certain the super glue is fully dry, squeeze the circuit board/visual inner screen display again to see if its all sealed. If nothing comes out... You might have fixed the leaking at least.
So, for this part, if it does have enough screen juice (LED me-thinks.....) Cross your fingers it does.... Close it up. Basic tape job should do fine. Make sure it would be taped equal to when it would be screwed-closed up...
Plop a battery in. Keep those fingers crossed. Then wait like normal and hope something shows up. If it does... Yay, Mini party... If not... I will try to think of another fix for it.
Note: This is random idea. This is what I would do to try to fix it. I really wouldn't know if this would fix it or make it worse... so its your call. Sometimes, my fixes work, sometimes they need to be re thought.
If you try this, do be careful. Make sure your hands are clean... Hand sweat/grease can ruin the circuit board. Don't squeeze too hard on the board. The ink might come running out, You might not find the leak at all.... If you can find the leak, at least that would give you a better chance of reviving this v3.
If you try it, I wish you the best of luck. I am nuts and so are my ideas.... You have been warned. :kuribotchi: