Fanuc 0M - Spindle Motor Module Alarm 09 / 30

From one day to another we got problem with Spindle Motor Amplifier.

There are 4 Fanuc modules: PowerSupplyUnit , SpindleAmplifier , XY-Amplifier , Z-Amplifier

Few seconds after power on with main power switch (not user control panel) SpindleAmplifier (A06B-6078-H211 #H500) shows Alarm Code 09 (overheat). This turns into blinking dashes ( not ready) after another second. This fault condition refuses enable PowerSupplyModule(A06B-6077-H111).
When I press ON switch at user control panel there appear 3 alarm messages ( 414,424,434 Servo Alarm XYZ) as result of disabled PowerSupplyModule. After 1-2 seconds there are 2 more messages 409 Servo Alarm serial err and 1006 Sp Motor Alarm.
Now SpindleAmplifier shows Alarm code 30 (excessive large current).

I dismounted SpindleAmplifier and checked IGBT bridge but could not detect failure. There was some dust on IC legs --I cleaned everything, removed 100A super fast fuse (to disable power pcb) and mounted all together again. Started from beginning but absolutely no change.

Any idea, suggestion or recommendation welcome.

Best Regards

Manfred