Long story short. i bought this machine a year ago and would not home just alarmed out z overheat. So when i had time i disassembled the 3 axis motors and changed all the brushes. Then retried to home and the Servo distribution smoked (literally).
so called my Haas HFO to install a new SDB. After the install the Ground fault 175 alarm cam and has not gone away. They have come 3 times and the hours are adding up 15 hr. They have replaced the Motive board and a nother SDB.
Now this gets interesting they installed a new IO board and then when you try to home or reset it would short out and reboot the control The screen would flicker and reboot but he did get it to home somehow manipulating it
but no movement and it alarmed out following error and then back to shorting.

Reinstalled the old IO board and back to the ground fault. i don't want to pay anymore without progress of some sort.
They have disconnected all the 120 volt from the IO like tool changer and pump and all the motor cables even the power to the amps.

I asked if they could change the low voltage power but he said it has good voltage so he did not.

Could the ground fault be a low voltage power supply or low voltage distribution board or a Processor?

One more weird thing when you start the machine the tool release is on and the orientation solenoid is on. that was with both IO boards. the input in diagnostic is off but the output is on??

Thanks in advance
Art