Hi,
I have an Anritsu 610A that the span pushbutton is not working.
I have a 610B manual and it appears to be similar enough to troubleshoot by.
I'm planning to open it up and momentarily jumper across the 74C923 pins that correspond to the span switch.
If that works its probably the switch contacts or a wiring fault.
Has anyone figured out how to access the switch contacts so they might be cleaned/repaired???
It looks like "maybe" the front panel may come off?
Cheers,
Corby