MESA 7i76E burning out issue

So, change made, AC power component is gone and first small test job ran successfully. Hoping for the best . Thank you again!

I finally found the real cause.

Today i got the amplifier fault on another joint (joint 0) and I found that it the problem happened whenever I turned on the spindle.

After several attempts to measure the ground connections the machine stopped in a position where I found the machine frame was not grounded.

The reason: The spindle connector got loose. The machine frame was grounded through the spindle cable, and that cable had become loose.

All I had to do was tighten the screw of the connector. Ground connection works reliably again and the machine runs well. Phew.