In order to help narrow the cause of on-going but rare timing comparator discrepency with the CNS clock at EY, I installed a rubidium clock on port 4 of the same comparitor.

The clock is on the floor under the computer rack.  A BNC cable runs from the clock under the roll up door, and over the racks in the CER to the comparator.

Port 7 of the comparator didn't work.