Seiko

Seiko Caliber 7A48: Quartz Chronograph Movement Guide
Factory specifications and practical moon-phase/date setting for Seiko’s 15-jewel 7A48 quartz chronograph, illustrated with three original VWS watches.
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Seiko Caliber 7A38: Quartz Chronograph Movement Guide
Explore Seiko 7A38 chronograph specs, functions and day-date controls, with original VWS 1984–1986 watch examples.
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Seiko Caliber 7T92: Quartz Chronograph Movement Guide
On a Seiko 7T92, the hand that appears to stop after about ten minutes is not necessarily reporting a fault. It may be performing exactly as Seiko designed it to: the 1/20-second counter rests whil...
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Seiko 6139 Pogue: Models and Variations
A reference-focused guide to Seiko Pogue 6139-6002 models, yellow and black dials, Skylab history, movement design and collector identification.
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Seiko 6139 vs 6138: Vintage Automatic Chronographs Compared
Compare Seiko 6139 and 6138 automatic chronographs, their timing registers, winding systems and buying checks using original VWS archive watches.
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Vintage Seiko Chronograph History: From 6139 to 7A38 & 7A48
Trace Seiko chronograph innovation from early mechanical stopwatch watches to the multi-register analog quartz era, with real archival examples.
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Seiko Sports 150: Models, Features & History
Explore the 1980s Seiko Sports 150 chronographs, comparing real 7A38-7130 and 7A38-713A watches, case details, quartz functions and collecting checks.
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