This is an old gameshell and i’ve had plenty of memories on it, but one day, it broke. I charged it and the screen turned on, but when charging the devboard makes squeaking noise, i got worried, dont know what is the problem, is it the devboard or the battery.
I think no one can give any solutions for this because it could be anything.
I would try everything independent of each other. Measure the batteries, … but sorry, no more tips. Search for a local electronics store or person.
Or order a new one. It’s worth it.
Good luck!