Zenza Bronica ETRSI - Zenzanon 75mm f2.8 - aperture stopped

[Rosssiiii]

Hello



i have tried to use the Zenza Bronica ETRSI - Zenzanon 75mm f2.8.



The machine currently has the bronica_etr_si_motor_winder-ei mounted and there is no battery in the body of the machine or in the winder.



The aperture preview works fine but I simply can't rotate them to replace them.



What i can do to understand where is the issue ?



can i try to put the battery in the winder and use it to see if change anything ?



can i try to remove the lens and try to change the diaphragm when the lens is not mounted ?