There have been some undocumented changes made to the analog scan generator card. Some of the relays are missing and there is an additional relay located on the back of the card. I traced these changes on the card and through the microscope to a panel on the back of the microscope. I had been unsure if this panel was for monitoring of the scans or for adding an external scan generator.
This will be extremely useful later in this project when I replace the internal analog scan generator with a computer controlled digital to analog converter.
The jumpers shown in the right of the picture power the relays that switch the input to the scan amplifier from the internal saw wave generator to the external inputs from these BNC connectors. These are obviously a revision to the board because they have been added by splicing the relay into cut traces on the analog scan gen board.
Besides the x and y scans the other inputs are for screen blanking which I will not need, and the video output the other connection I need to digitize the microscope. Having these connections already made will make my job a lot easier and make for a neat installation when I add my computerized scan generator and recorder.