We decided that it would be nice to add lamps to the connecting circuit and exchange line relay sets. To do this we took a wire from U12 (battery) and a wire from one of the contacts on the B relay to the lamp terminals which are normally redundant.
Below, first video we made shortly after starting work on the pabx7. if you watch closely you can see the uni-selectors stepping. You may also see that occasionally when 0 or 9 is dialled the connecting relayset wiper does not return to normal as it should, further work was needed to clean contacts.