Seiko 7A28 Movement Details

Seiko caliber 7A28 is an analog quartz watch movement. Production started around 1983.
Search eBay for watches with this movement.

Sub-brands: Sports 100, Speedmaster, SQ
Battery:SR936SW / 394 (Silver oxide)
Accuracy:±15 seconds/month
Day / date?No
GMT / world time?No
Chronograph?Yes
Alarm?No
Hacking?Yes
Rate:32,768 Hz
Number of jewels:15
Size / diameter:29.0mm
Height:3.5mm
Development division:Suwa (Nagano Prefecture, Japan)
Notes:The world's first analog quartz chronograph and, unlike many other quartz chronographs, uses metal rather than plastic parts making it fully serviceable. Used in watches supplied to the British and South African air forces. Has a battery life indicator function. The same as cal. 7A38 but without day and date display.
PDF guides: Technical guide : 7A28A
Related movements: 7A34 7A36 7A38 7A48 7A54

Part Codes

Stem code: 354726
Screw codes: 022233 (dial screw), 022286, 022341, 022424

Videos


Related Articles


Images

↑ Back to top