| Manufacturer | Seiko |
| Caliber Number | 7B72 |
| Movement Type | Solar-powered, radio-controlled, quartz |
| Display | Analog |
| Jewel Count | 0 |
| Frequency | 32,768 Hz |
| Capacitor Part # | 3023 24M, 302324M (unconfirmed!) |
| Power Reserve | ~9 months on a full charge |
| Integrated Circuit | 2 piece IC – Oscillator, frequency divider, drive/reception circuit |
| Driving System | Step motor |
| Hand Count | 3 |
| Functions | Central hours; central minutes; central seconds; date at 3:00 |
| Other Features | Radio signal reception for automatic time setting |
| Hacking Seconds? | Yes |
| Country of Manufacture | Made in Japan |
| Known Models | Seiko Astron (Ref: SBXY029, SBXY031, SBXY033), Seiko Modellista (Ref: SBTM331) (Add your watch to the comments below…) |
Seiko caliber 7B72 is a radio-controlled quartz movement that runs on a rechargeable battery (aka capacitor) connected to a solar sensor under the dial which collects and stores energy from light. Timepieces with this movement were introduced in late 2019 for the Japan domestic market (JDM).
Radio-Controlled Timekeeping:
The radio-controlled features means that watches with this calibre are able to connect to radio towers (Cesium Atomic Clock) in order to receive data about the current time. The watch then uses that information to automatically set the time accordingly.
In Seiko’s own words:
“This watch sets the time and date by automatically receiving a radio signal at a fixed time. It automatically receives a radio signal before 2:00 AM, 3:00 AM and 4:00 AM.” -Seiko 7B72 user manual, page 17
Similar Calibers:
There is a similar Seiko caliber 7B62. The 7B72 and 7B62 share the same manual, however, it is unclear what the differences are. If you know more about this, please discuss it in the comments below…
Additional Resources:
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