Very admirable work, but I can't help but feel like they are late to the game.
I work on those handhelds, and they're all slowly dying. The onboard flash memory is starting to fail more often in older units, and even newer ones are prone to developing significant screen issues. Parts are mostly still available - but some, like the power boards, are getting harder to find.
It's not as easy to swap the primary PCB as a Game Boy. And the chips are not off-the-shelf, so donor consoles are the only source of replacement chips.
This project looks fantastic, and I hope it succeeds. But the consoles themselves may be too old for this to have much impact.
all 5 comments