fanuc spindle drive AL-12?

[landslide1]

I have an AL-12 problem on mt LB-10 drive.

I found a bad transistor module and replaced it. I scoped the firing board and the wave forms are good.

when I run the amp without the motor connected it gives AL-02 (no movment on the spindle sensor) but when I plug the motor back in it gives AL-12.

I know this points to the motor but I have meged it to around 500Mohms between each lead and earth. Between the windings give consistent 0.3ohms (not a milli ohm meter).

what else might be the cause of AL-12?

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[vishal105]

Please check drive to motor wire. is it short or not?
If you still facing same issue then check igbt of drive module.
For any detail pm me or mail me on vishalsojitra.dh@gmail.com.

[landslide1]

motor is not shorted as far as i can tell. I have megged the motor from U-ground, V-ground and W-ground and all are arounds 500Mohm.

IGBT (transistors) aren't shorted.

should I be megging from U-V, V-W and U-W?

[vishal105]

I have megged the motor from U-ground, V-ground and W-ground and all are arounds 500Mohm.

IGBT (transistors) aren't shorted.

should I be megging from U-V, V-W and U-W?

Yes check that also. How can you check igbt?. If igbt not short then issue in wiring please check that also.

[landslide1]

Yes check that also. How can you check igbt?. If igbt not short then issue in wiring please check that also.

I'm checking the Igbt using a transistor diode check method as per the manual. I fully disconnected the transitor blocks and tested them. they are all ok with no shorts.

the wiring looks ok but I don't have a wiring diagram. I have checked the varistors and diodes for shorts.