[dan60231]

I'm running a friends 1999 VF3 and today when I shut it off Z axis dropped until hit the table. It went down slowly and really didn't cause any damage, but I've never seen a CNC mill do this before.

Anyone have any ideas on this?

[Pondo]

The counterbalance is compressed gas (nitrogen???) and leaks out a little sometimes. A Haas tech can recharge it or replace it if needed.
When it is powered up, the Z servo holds the head up. When it's powered down and the counterbalance is not fully charged, the head drops (like you've seen).
There should be a gage and a little placard on the side that says what the pressure should be for various models. I believe it says if it needs to be at the top of the travel or not too.

[dan60231]

Thanks for the fast reply. I'll tell the machine owner and have him get a tech in to get it taken care of.

There also must be a door over ride command somewhere. When I powered the machine back up it says door open. I need to find the parameters and reset it so we can run the machine.

[Pondo]

Setting 51 disables the door interlock. It resets to ON every time the machine is powered down.
In settings, type in 51 and hit cursor down to jump right to it. It's on the page with all the most commonly changed settings.