7751 Moonphase - Chronograph Use Slows Watch

[Folkvisor]

Do 7751's have a chronic problem with the chronograph complication? The watch keeps excellent time and there is no problem with anything else but every time I turn on the chronograph the watch slows down drastically.

I've checked the chronograph parts and nothing seems out of place and no foreign objects are present.

[nickelsilver]

The 7750 is one of the most reliable and well performing movements of all time, with and without the chronograph engaged.

 

So something isn't right.

[Folkvisor]

O, absolutely. It keeps excellent time.