I'm afraid you will have to dismantle your Zeiss a bit further... But it is not too difficult. I started my "career" with instructions kindly provided by Mr. Richert: http://www.davidrichert.com/zeiss_52...id_shutter.htm
Some more information:http://benoit.suaudeau.perso.neuf.fr...ir-manual.html and: http://www.rolandandcaroline.co.uk/repair.html