Check that the AC mains (line) input power supply is not experiencing interruptions.
Check that the machine does not share a power supply with any other equipment. Sharing a power supply may cause the safety over current device to switch off the electrical supply to the machine. This would cause a 303-777 fault. If possible, ensure the machine is connected to a dedicated power supply.
Check the fault history file for other 303-XXX-XX fault codes. If the 303-XXX-XX fault codes occur randomly, the cause may be due to electrical noise.
I had to troubleshoot a work centre 5875 and found multiple faults at various times for the past few days. fault code 303.777.00. all I can find online is that its a hardware fault. mainly loss of power. the users that scan and print to it say they have to reboot the machine (they unplug it from the wall) everytime it stops working. and the xerox support technicians (3rd party company) say it's a network issue not the machine. I find that hard to believe since nothing else on the network drops and it suddenly started happening. any one have this issue?