BARD Site Rite 5 System Malfunction Error Code Displayed

Hi There I am having a problem with locating a fault on a BARD Site Rite 5 system. The system error corresponds to a "System Malfunction Error" and the system will not work. I have looked over the PCBs but could not find a fault, dose anyone know what could be wrong with the system. Any Help Is Grateful! Thanks for reading