[markp]

Hi, I just picked up a nearly new DMC103v, only 180 hours, loooong story. Everything works great but the z axis will occasionally drop very slowly after estop is pushed at the end of a run before shut down or sometimes during operation if the door open switch is activated. Only happens once in a while and the brake usually kicks in after a few inches of drop. What was the wiring change you indicated you had made? I would like to try it. Thx Mark

No, thats not the connectors. At a new machine the motor connectors are new as well. They have made a fault in the wiring of the CNC and instead of connecting to the customers, they wait until the customers call her. And that was not the only fault in the new machine.

And the connectors of the siemens Motors don't make any problem, I have disconnected the toolrevolver more than 50 times. Never have a problem with this. But the connectors from a dozen years ago are maybe better than the one produced today. Another problem with the machine is the doorlocking, the switch will defective after some years, because of the tremor of the toolchanger.

@kevork_gr and others: If you give me your email adress, I will send you the changes. It works only with the 840D contol.

[DMGService]

If the Z axis drops when hitting the e-stop button, opening the operator door, or when you finish using the handwheel, the problem is the Z axis Brake inside the Z axis motor.

In each of these 3 cases, the power (electricity) that is holding the Z axis in position is taken off, and the mechanical/electric brake is applied.
The Brake is normally locking the Z axis in place when in e-stop or the operator door is open. When you activate the drives to the 3 axes by closing and locking the door, or by entering hands free mode (Hanswheel) Power is applied to the motor, and a split second later 24 Vdc is sent to the Brakes, releasing them. That is the "Chirp" noise you hear at this point.
The same thing is true when you deactivate the drives by opening the operator door or pressing estop. First the 24 Vdc is dropped from the Brake, and then a fraction of a second later, the electricity from the drives is turned off. This fraction on a second gives the brake time to lock the Z axis in place, before taking off the power to the motor.
If the Z axes drops at this point, it's because the brake is failing to apply fast enough, and must be repaired or replaced immediately. If left like this, it will get worse until the Brake is slow enough to apply that the Spindle crashes into the table.