Z-Axis wont home out, Z position dropping on VTC-200C

Fired up our VTC-200C this morning and the Z-Axis wont go home. It will move up and down, but it just runs into the soft limits.
When the control first fires up the Z-axis drops momentarily. When i press the E-Stop the Z-Axis will start dropping again until release the E-Stop and hit reset, again.

There's no alarms on the machine, but the MR-J2-CT servos both have an M01 0101 "No operation mode" alarm.
The manuals state the following for this alarm
Cause - The operation mode is not designated, or the operation mode was changed during axis movement
Remedy - Correctly designate the operation mode.
I think this is tied to the Z-Axis moving?

Waiting to get a call back on this issue from our repair guy, but i figured I'd post it here just to see.
Any help would be appreciated.

Did you ever find the problem ?
I have exact same issue with mine.

The root problem ended up being the brake on the z-axis motor. It was not holding the axis in position when powered off or e-stopped.
When powered off, the axis was dropping below the limit switch. I believe this was causing the machine to lose home position when powered back on.

We had to reset the home position in order to get going again. This is a quick rundown of the procedure to do that.
Go to Parameters
'Feed Velocity' Parameters
Find M8 and M9 values and write them down or take a picture! (these are the soft limit values for the control, very important!)
For M8 input 99999999
For M9 input -99999999
Power cycle machine for control to take new M8 M9 values.
(Caution! You just opened up the soft limits to extreme values. This means the control will not stop the axis from bottoming out on either side of the casting)
Manually jog the Z-Axis to the positive side of the physical limit switch (just slightly above normal home position). For our VTC 200C this was approximately 28" from spindle nose to top of table.
Press the 'HOME' key and move the Z in the negative direction. (might want to turn the rapid down for this)
Machine should move pass the physical limit switch and them pull itself back home like normal.
Return to the 'Feed Velocity' Parameters and input original M8 M9 values.
Power cycle the machine and you should be able to home out machine as normal when started back up.

Until you fix or replace the axis motor, placing wooden blocks under the spindle when shutting down the machine will at least stop the machine from dropping and losing position when powered off.