Okuma Alarm-D 4870 Invalid servo data selection
1->It is miss match between the Spindle chuck select switch condition and Selected Spindle Servo data after machine power on.
Probable Faulty Locations
The Spindle chuck select switch condition was changed, when the machine was power off condition.
Measures to Take
Turn the power off and turn it on after making match condition between the Spindles chuck select switch and an actual spindle chuck.