Also does switch 24 show in the switch edge test as this switch should be always closed?

As far as the clock goes, these switches are all  connected to an extra board and may be worth checking the connector at J5.

yep 24 shows up but I didn't think of mentioning it. cant get 87 to register out of all the optos. I have a spare opto pcb but not sure it works. I soldered sockets for these chips but I don't think well. I had the old fuse error problem, so bought a aftermarket from great plains that has leds to show the status of optos. at the moment 2 are flashing on/off continually.