Favre lueba 251 can’t let power down manually

[Crockpot]

I just got this watch and wound it and to put on timegrapher to make sure it doesn’t have any major problems before I took it apart for service but I can’t get it to unwind so I can take it apart. It winds smoothly and runs great for its age I got it for a good price. When I realized I couldn’t take the power off I cleaned and oiled the balance jewels. But it’s weird because I can turn the stem and hold the click back and it unwinds about a half turn of the crown and then the crown just turns freely and the winding gears stop turning. What’s strange tough is it winds up smoothly but something stops it from unwinding with the crown.Here’s a pic of the click circled. Is there something I’m missing? Thanks

[Nucejoe]

 FL 251 is a twin barrel ,   I guess you have depowered only one. 

 

 

[Crockpot]

The barrels both turn together, but after manually unwinding about half a revolution the winding gears stop and the stem and crown just turn backwards freely. But it winds up fine and runs fine. When I hold the click back the crown turns a few revolutions and when the winding gears stop the crown turns backwards freely. When I turn the crown the other way it winds properly. Something locks it up while letting the watch unwind with click held back.