Aloha, thanks for your reply. Contact TREW audio in LA. They have many years experience with Nagras. Some time ago an employee broke away from Trew and specializes in Nagra repairs, his name I recall was Forester. They could direct you to him. Since he works on Nagras he would probably have the info you need. Happy Thanksgiving and happy searching.
Aloha, more Nagra info. Contact Trew audio in Nashville, TNN. ( Jake Garrett ) There was a full time Nagra employee when Nagra had an operation in Nashvville. This person may have all the data you are looking for. Cheers