As Lincoln mentioned Verify the Card in the DM switcher and the Program definition. 2 Series CPU Card used 2 digit Hex the CPU3 changed to a 3 Digit. This bit a top Corp 500 when upgrading the cards for security reasons and the code was not updated. You can Change the DM Card as previously mentioned to run in legacy mode True blue has a console command to do it. We had issues where 4K Scalers worked fine buit Scaler-C's would not pass control until legacy mode was enabled. Good Luck
Nathan Rader