I just purchased a used 500. I am pretty sure that it probably will come to me with the way this individual had it programmed and global settings. Since I don't have the manual, the first thing I would like to do would start with out anything programmed and factory setting in place. I know he had just did the most current upgraded firmware so won't have to worry about that. Is there like a master re-set setting so the scanner would be blank of all frequencies to scan?