My grandparents have a DSC Power 832 (PC5010) that they haven’t used for a while. They have forgotten their codes and the installer wrote nothing down. System was installed 25 years (ish) ago and the installer has since left town. Trying *8 5010 gives me an error tone. Should I try any other codes? Is there a different way to access programming? Many zones wired into the panel. Would prefer not to have to factory reset the panel. Don’t have a lot of knowledge with DSC. Anyone have any suggestions? Thanks!