I recently serviced a watch with a steep learning curve. I guess I though a quartz watch, was a quartz watch. But, alas, they are not!
The watch was a Piaget Caliber 8P2. I tested the electronics before agreeing to service the watch because I knew that I was unable to order parts from the manufacturer. Quartz watches are usually straight-forward and they usually don’t require parts as long as the electronics are good, so I took a small gamble and decided to service the watch. Boy, was I in for a surprise!
This caliber has some definite peculiarities, and it had been tinkered with in the past to add to the difficulty of the repair. My first clue that this repair was going to be anything but ordinary was when I removed the dial and found a gooey mess all over the movement. I was pretty sure it didn’t belong there and some fellow watchmakers confirmed it for me, as well as warning me that the endshake on the rotor was very particular on this movement and only adjusted with a special key.
Someone had glued the dial in place with rubber cement, or perhaps some kind of a grease. In fact, once the movement spacer is attached to the movement the dial will stay in place by the friction of the outside edge of the dial against the lip of the movement spacer – no glue necessary! — This was remedied with a cleaning but it was the adjustment of the movement that took some work and some serious learning.
First, the time on this movement is set by an electrical switch which is activated when the crown is rotated in either direction. This requires that there be two stators with opposite polarity on the rotor of the watch. This was not a big deal, except that this watch has two different rotors in series in the gear train. The first wheel of the train is attached to a permanent magnet which rests in the two stators which control rotation in both directions. The second wheel in the train is also attached to a permanent magnet which rides inside of a multiple-polarity stator and I’m not sure why. These two wheels have to positioned properly so they work with each other and not against each other. Any misalignment will keep the movement from working. Proper alignment ensures that the hands move smoothly in both directions.
Setting the time on this watch is done electrically by rotating the crown. The clutch wheel (sliding pinion) engages an electrical switch instead of a setting wheel. When the stem is turned one way the hands turn in one direction, when turned the opposite direction the hands turn the opposite way. After I got the watch running smoothly I had problems with the switch and the watch wouldn’t keep time properly. Turns out the spring which interacts with the sliding pinion was ready to break, and eventually it did, but not until the customer received the watch.
Final tally: it took 3 services within three weeks to get this watch up and running properly, but only because I had to learn all about this movement. The learning curve was steep but I am prepared for the next one I encounter, should I ever see another one. If the manufacturer would disseminate technical literature I could have saved myself a lot of trial and error learning, but then I wouldn’t have learned these lessons all at once.
Watchmaking is full of learning experiences like this. It is important to be able to figure out how things are supposed to work, because the proper documents are not always available, or even if they are, pictures are not the same thing as the actual watch.