Many thanks to the both of you for your articles on repairing the HP-67 card reader which were a great help to me in reviving the reader in my newly acquired '67.
Having carefully dismantled the '67 I could see why the reader was completely dead, most of the white balls, and the pich roller, were solidly encased in some of the remains of the gummy wheel which was preventing operation of the metal blade contacts. However, after a good clean, taking care not to disturb the metal contacts, and rebuilding the gummy wheel, everything went back together (without too much lost time chasing errant balls and leaf springs) and I now have a fully functional '67.
Many thanks again.
Best
James