Fortis with 7750 based movement question

64Wing · Mar 29, 2020

Hi all,

I have a Fortis Flieger Professional Chronograph that houses a 7751 movement.

Had it for several years now.

Anyway, yesterday I picked it up off my dresser and noticed that if I held it such that the dial was perfectly parallel to the ground (face-up) the rotor would spin as if it were directly connected to the crown whilst winding. Felt like it was fully wound but shouldn't have been.

Thoughts??

Caliber561 · Mar 29, 2020

Sounds like a case of "helicoptering rotor." If you search it up, you'll see it's a fairly common issue associated with ETA/Eterna-style reversing wheels. If I remember correctly, it has to be solved by servicing the watch.

Edit: Disregard the above. I was under the impression that the 7750 had bidirectional winding.

Vercingetorix · Mar 29, 2020

The 7751 winds in one direction. You are probably experiencing rotor wobble. It is freewheeling the opposite direction it winds.
https://forums.watchuseek.com/f2/why-does-valjoux-7750-wobble-139824.html

Archer · Mar 30, 2020

64Wing
if I held it such that the dial was perfectly parallel to the ground (face-up) the rotor would spin as if it were directly connected to the crown whilst winding.

Reversing wheel is not unlocking when manual winding. Service required.

Cheers, Al

64Wing · Mar 30, 2020

Thanks all for the replies!

I had planned a service anyhow...in my own way of thinking: at least I'll feel like it'll be more worth sending it in since it now exhibits an issue.

Off to RGM it goes!

Fortis with 7750 based movement question

64Wing

Caliber561

Vercingetorix

Archer

64Wing

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