Its been a very long time since I worked on a Fanuc controller. It sounds like you have encoder problems. I would doubt that all encoders have failed at the same time unless your power supply has blown them up. Have a look at the power supply and check the voltage is within the required parameters for your machine. With most controllers the +5volts needs to be a good solid supply normally around 5.1 volts and shoudnt drop. Also could be a fault with the encoder feedback pcb or maybe the machine settings have been corrupted. Unfortunately I cant tell you how to check them.

Regards

Ian