Safeguard on its own only means that the logic circuits have disabled the mechanism from operating because a potentially damaging situation has been detected, and which can be caused by one of many things, so its really a case of whether or not any other info appeared on the LCD like error codes etc, as these would give a pointer as to the possible location of the fault. Its also noticed that you posted under another persons heading where a model number was mentioned, so in the interests of accuacy the question would be "do you have the same D93U model as is mentioned in the other persons posting?"