Are there any fault codes appearing on the power supply or amplipher? that may give you more detail,
else, I have had limit switches stuck or jammed with chips causing the alarm to come on.
I think you can (if you have the manual) look up in the parameters the fault down to the bit level, which will also tell you if it is an over-voltage,current ect type of alarm. I have seen over-current alarms with dull tools on the z-axis...
hopefully "Al the Man" will spot this post and help you out as he is well versed in the fanuc systems.