Today I’m servicing the Movado Datron HS 360. This Movado featured the Zenith 3019 PHC movement (also used in the Zenith El Primero). Released around 1969, it was touted as the first automatic chronograph (although both Heuer And Seiko were close to follow with their Chronomatic and Speedtimer). It featured 60 sec./30 min./12 hour count wheels, a quickset date, 50-hour power reserve, and a frequency of 36,000 BPH. The date calendar wheel also features an instantaneous date change similar to the Rolex Datejust design. For more information on the first automatic chronographs visit “50th Year of the Automatic Chronograph: Who Came First?”
Quality & Condition
The movement is impressive, well designed, and built to last. This watch came into the shop in pretty good shape, although there were several repair issues. The hammer spring was broken (the spring that snaps the Chronograph wheels to zero when reset). Also, the very thin spring that snaps the date wheel forward was broken. I was able to source the hammer spring from a supplier overseas, but I had to make a new calendar spring.
Also, black thick glue was used to try to seal the stem and chronograph pushers. I’ve seen this before, and although it may help protect against moisture intrusion, it is a poor solution and an absolute mess to clean up. When I complete the service, the case is sealed from dust intrusion and reasonable water resistance. But a vintage watch such as this should not be worn around water or in the shower, and not be worn while swimming.
Calendar Wheel Spring Broken 
Hammer Spring Broken 
Previous “gasket glue” Mess
Servicing Procedure
Serving a complicated chronograph requires that all parts, screws, and springs are completely disassembled and inspected. Minor adjustments have to be made to accommodate for wear. A high-quality movement such as this does provide fine adjustment screws, but sometimes springs and arms have to be manually adjusted.
After cleaning, repair, and proper lubrication, the watch ran very well (most positional differential rates were under 3 seconds/day). All of the chronograph parts operated smoothly and the watch was restored to excellent working order. The pushers were badly worn and were replaced, a new crystal installed and the movement cased. Although showing signs of wear, the watch is in good vintage condition.
For information on sending in your chronograph for repair please visit TimePieceShoppe.
