After entering the market of quartz movements with the caliber UMF 28-40, the east german VEB Uhren und Maschinenfabrik Ruhla (UMF Ruhla) launched a number of quartz movements. Their one but last one was the caliber 13-33, which was produced in high numbers between 1984 and 1990.
It has a diameter of 11 1/2 lignes and uses the compareatively large battery type 395 (SR 57) with a diameter of 9.5mm.
On the base plate of this pillar movement, you see, that two bearings, rotor and first transmission wheel, are equipped with rubies.
The electronics module is already pretty boring, only the use of a trimmer capacitor for adjustment is noteable.
The gear train consists of a rotor (rotating magnet), a transmission wheel, the center second wheel and the third wheel, which drives the hands on the dial side.
The magnetical rotor is difficult to keep in position, when it is not beared on both sides. For this photo, several attempts and a plastic tweezer were required.
The UMF 13-33 also uses a Lavet stepper motor, on which the rotor rotates 180° each second and advances the gear train a step. This principle is common for all modern quartz watches, as well as the quartz frequency of 32768 Hz.
The date indication with its quickset mechanism (second crown position) is a bit complex. The large switching wheel at 11 o'clock carries a moveable switch finger made of plastic, which allows to correct the date even during the regular switching hours (between 10:30pm and 12pm) without damage.
At 3 o'clock you see the yoke keyless works. In the middle crown position, the date corrector engages with the teeth of the date ring and advances or turns it backwards.
This movement is a kind donation from Mario. Thank you very much for the support of the movement archive!