I recently serviced this 1940's Universal Geneve (UN) Calibre 481 Tri-Compax Triple Date Moonphase chronograph for a ClockSavant customer. It is one of the most complicated volume production wristwatches made prior to the resurgence of mechanical watch manufacturing in the 1990's. As the wristwatch became the norm, people sought more functions. This watch combined a chronograph, hour recorder, triple date and moonphase indicator. While a nice example, this watch was replete with the shortcuts I commonly see-- footprints of someone fixing "a problem" rather than the whole. As the watch ages and cries for help (clean me, lubricate me, address wear, corrosion, adjust me, fix me), it begins to lose power. This many functions demands power. Optimizing power is difficult work. In the past, the watch was likely stopping when the minute counter register wouldn't advance so they tried to bend the minute register jumper. This jumper holds the minute wheel in-place for incremental stability but its resistance increases power demand. While adjusting these jumpers when new is not uncommon for some calibres, typically something else is wrong such as needing to step-up and properly service it. This is why so many minute jumpers are broken. The jumper was broken then glued. It didn't end-well-- for the future owner, the watch stopped running with a piece of the jumper lodged into the balance. They also fouled chronograph adjustments in an attempt to raise power. They refinished the dial but improperly painted the rear. Paint made its way into the movement. My feeling is that the dial-side hadn't been fully disassembled in some time yet the back of the watch had seen recent work. You see corrosion that built-up from a lack of proper servicing and "cleaning" without first fully disassembling the dial-side. Once fully serviced properly, watches of this complexity require extensive testing and ongoing refinement. After full servicing the watch is running beautifully once again.
