Rare Vintage Seiko Alarm Chronograph Calculator C439-5000 Digital Watch JDM 80s

Up for sale is a Rare Vintage Seiko Alarm Chronograph Calculator C439-5000 Digital Watch, a highly collectible Japan Domestic Market (JDM) model from the 1980s. Powered by Seiko’s advanced C439 module, this impressive multifunction watch combines alarm, chronograph, calculator, calendar, and timekeeping functions in a distinctive design that perfectly captures the spirit of the early digital era. The watch is in working condition and all features and functions are operating properly with one exception. Some of the calculator keypad buttons do not consistently activate the module when pressed with normal pressure. I have intentionally avoided pressing these buttons firmly, as I did not want to risk damaging any potentially fragile internal components. Due to this issue, the calculator function should be assumed to require attention or repair. Aside from the inconsistent operation of some calculator keys, all other features and functions of the watch are working properly. The watch is fitted with a genuine Seiko stainless steel bracelet. However, I am unsure whether the bracelet is original to this particular watch. All other parts of the watch are original. An interesting feature of this example is the caseback engraving, which reads 贈 クリナップ (Presented by Cleanup), indicating that the watch was originally presented as a corporate gift by the Japanese company Cleanup Co., Ltd., adding an additional piece of provenance and history. The watch is in very good physical condition with signs of use and age consistent with a vintage digital watch. The photos best describe its physical condition. Key Details: • Brand: Seiko • Model: Alarm Chronograph Calculator • Reference: C439-5000 • Module: C439 • Era: 1980s • Origin: Japan Domestic Market (JDM) • Movement: Digital Quartz • Features: Alarm, Chronograph, Calculator, Calendar, Timekeeping Functions • Bracelet: Genuine Seiko Stainless Steel Bracelet (Originality to Watch Unknown) • Condition: Working Condition with Calculator Keypad Issue • Originality: All Original Parts Except Bracelet Originality Unknown • Caseback Engraving: “Presented by Cleanup” Corporate Presentation Watch A rare and increasingly difficult-to-find Seiko calculator watch from the golden age of digital watchmaking. An excellent addition to any vintage Seiko or early digital watch collection. Ships carefully. Feel free to message me with any questions.