Seiko 8R48A Technical Manual

PARTS LIST / TECHNICAL GUIDE
Automatic Chronograph Cal. 8 R48A/8R49A
[SPECIFICATIONS]
Item
Cal. 8R48A
• 3 hands (hour and minute hands, and small second hand at
3 o'clock position)
• Calendar (Date: Date disk)
Driving system
Additional function
Crown operation
Normal position
1st click position
2nd click position
Vibration per hour
Daily Date
Loss/Gain
Standard rate
for movement
Regulation system
Lift angle of the escapment
Coutinuous operating time
Number of jewels
Cal. No.
Cal. 8R49A
Automatic winding with manual winding mechanism
• Stopwatch function
Measures up to 12 hours
• Semi-instantaneous date change mechanism
• Second hand stop function
Manual winding (clockwise only)
Date setting (counterclockwise only)
Time setting (Hour and minute)
28,800 (8 beats per second)
+ 25 / - 15 seconds at normal temperature range
(Between 5°C and 35°C )
Testing
positions
Measurement
(daily rate in
seconds:s/d)
ETACHRON system
52 °
From fully wound to stoppage: Approximately 45 hours
34 jewels
8R48A/8R49A
Movement
[Bridge side]
Movement size
• Diameter
• Height: 7.62 mm
Instantaneous rate at T0
(Fully wound condition)
6 o'clock
Dial upward
at the top up
+ 15 s/d
+ 20 s/d
– 5 s/d
– 10 s/d
1/24
[Calendar side]
Outside: Ø 28.6 mm
Casing: Ø 28.0 mm
Isochronous fault
9 o'clock
Dial upward
at the top up
+ 20 s/d
± 10 s/d
– 10 s/d