Spindle motor spinning with S800M3; then suddenly the motor stopped (slowly, without brake function), load meter went up to 180%, and display showed OT 102 - excess velocity error
Sometimes it can get started, but after a while (1-2 min) the loadmeter starts to show higher and higher load, increasing noise from spindle motor, then it stops again (OT 102)
On the A50L-1-0125A transistor module I compared the voltage on BX, BY, BZ and when the motor was running It was about the same voltage on all 3, but when it starts to fail, the voltages change on BY and BZ.
I checked the motor feedback signal on CH3, CH4, CH5, CH6, CH7. Everything seems okay. I changed the A50L-1-0125A module, but it is still the same problem.

I need some tips, and electrical wiring diagram / service manual on spindle servo system.
AC spindle servo unit A06B-6052-H004
A16B-1100-0091 / 070 (R911)
A16B-1100-0080 Ed.No.:06D
AC Spindle motor Model 3 Type A06B-1003-B 352

Thanks in advance for any help