Xerox 5624 Copier - U4 System Fault

[TAMKO]

We have an old Xerox 5624 Copier and it has a U4-System Fault code on it an will not work.

What does this mean and how do I fix?

Any help would be greatly appreciated.

Thanks
K at TAMKO

[Mr Spock]

usually a fuser temp code
turn on while holding 0
20 start 3 start
turn off then on
if ir returns call a tech to fix fusing unit.