I have a faulty module in a Casio Game 401 (QW245). Most of the functions are fine but the game goes crazy at about level 3 and totally freezes, requiring a AC reset.
Even switching back to time mode while it starts its odd behaviour doesn't fix it and it freezes shortly afterward.
The watch should take a BR2020 (obsolete) and I've tried with a new CR2016 and CR2025 but same behaviour so I doubt it's a battery issue.
Any hints? Or see my Wanted post if you have a working module/circuit for sale.