Hi everyone its paul from test cal instruments. I have tried to realign my yto in my various 8560a units and cant because the instructions in the 8560a service guide are incorrect if a tracking gen is installed. there is no way to select ext mixer unpre, and there is no external mixer softkey in the aux control menu. it is removed once tracking gen is installed. so how do I realign or check my yto? the only thing i can think of is somehow deprogramming the unit to making it think there is no tracking gen installed on it. and then taking the lo output directly from the yto feed to my counter? or routing it into the lo dist amp as it would have been normally routed? im stumped can someone please tell me how to do this and also I would like to know how the analyzer knows there is a tracking gen installed. is that a software program or just a jumper like when adding opts to the 9 series? thanks !