Casio CD-401 Data Bank — 1980s OG, Fully Serviced, Regulated +0.01 s/day

A vintage Casio CD-401 Data Bank from the 1980s — one of the original calculator-and-data-bank hybrids that defined the era of the digital wristwatch. Full numeric keypad, calculator, memory storage, alarm, and timekeeping packed into a two-tone case with the unmistakable look of ’80s wristwear. Bench-serviced, fully functional across every mode, and regulated to essentially perfect rate.

Watch the bench walkthrough on YouTube →

Service Performed

• New battery installed
• New pusher gaskets fitted
• Case hand-cleaned only — no ultrasonic, to protect the integrated keypad assembly
• Pushers manually and ultrasonically cleaned
• Bracelet manually and ultrasonically cleaned
• All functions verified working — time, calendar, calculator, data bank memory, alarm
• Quartz regulation verified at +0.01 seconds per day on the Seiko QT-99 quartz tester

References & Markings

• Model: Casio CD-401
• Caseback: Stainless Steel Back, Japan M
• Serial: 517618
• Era: 1980s

Condition Notes

Honest vintage condition consistent with a watch of this age, presenting well after bench cleaning. Display is clear and crisp, all keypad buttons respond correctly, and the bracelet articulates smoothly with no stretched links. Case shows light handling marks under close inspection — nothing distracting at wearing distance. Detailed photos provided show every angle so buyers can assess for themselves.

Includes

• Casio CD-401 Data Bank watch on bracelet
• Full bench service documentation
• Quartz regulation reading on Seiko QT-99