How To Fix a Dead Casio Wrist Watch | DIY - YouTube
HOROLOGY CRAZY: Casio Module 394
Casio MD-502 Battery Change
Replaced the 394 module in my vintage MD-700 to bring it back to life. A bit small by modern standards, but a common men's size in the past. : r/ casio
Vintage Casio MRD-201W Module 394 Not Working Need Service | eBay