I bought a used MSO7104A a few months ago. It was last calibrated in 2009 and I have noticed some offset issues on the lower volts/div settings, so I decided to run a user cal. I connected the BNC cables from the trigger out connector to the front panel with three BNC tees as directed in the manual. However, when I run the user cal, it fails after running for less than 30 seconds with "Failure: Digitizer, failed, init for talon cal, setup chan1". The scope seems to work fine and it passes the self test. I have tried several different cabling arrangements with the same result. Does anyone know what this error means and if there is any way to either complete the calibration or roll back the calibration data?