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Gilt bridges, 5 jewels
From thewatchforum.co.uk
"Ricoh also developed a range of unusual movements around 1976 - the cal510 is the best known, with two setting buttons as featured in my recent post on this forum. There was also a similar cal530 with a single setting button. And there was a cal(forgot the number - perhaps 520??) with the two setting buttons on the back - this movement seems to have been used in watches with two movements and two analogue faces together in a single watch head."
From Electrifying the Wristwatch "The Riquartz 510 was still another ladies' watch caliber; it was launched in 1976. This was a round two-hand caliber with a diameter of 22.0 mm and a height of 4.3 mm. The hands were actuated by a six-pole, 60-second stepping motor with an axially magnetized rotor that directly moved the minutes wheel. The tuning fork-type quartz resonator was supplied by NDK, the integrated circuit by Hitachi.
The plate consisted of a brass-steel sandwich; the steel part with two jewels was on the dial side and assured an excellent magnetic shielding. Stopping the seconds-hand and setting the other hands were done electronically by means of two pushers."
Button B (lower button) advances the time forward by one minute. Button A (upper button) sets the movement going after adjustment. In order to set the time back, pressing button B will stop the movement and after waiting a period of time the watch can be restarted with button A when the time is correct.
CMOS integrated circuit marked for example "7G2 841" for 2nd week of July 1977, made by Hitachi.
Example: 3B4 reads as 4th week in February of the year 1973
Battery 384
Consumption 1.3 micro Amps
Battery life in excess of 2 years
Accuracy 15 seconds per month
The anti-magnetic shield under the dial forms part of the mainplate and carries the upper jewels.
