I have seiko sports 100 a547-5050 and have lost button A. Anyone know how to use another button in the button a aperture? thanks

Hi Daveyf welcome to the forum.
I do have a a547-5050 body here but don’t really want to break it as i’m just waiting to source a crystal. I did have a look and these are the other models(see below) that carry the same button. Because its a sports 100 these buttons are a lot larger with a spring inside. If you cant source one of these, julesborel.com may have one in stock. If that doesnt work come back to me and ill see if I can source one for you.

regards

Adam