Head Crash Analysis

The problem:After several hours of work the head tilt motor becomes unable to lift up the head. You don't need to use something like hard head kicks, continuesly lifting the head up and down (within its limits!) is sufficient. At the beginning you can hear the motor having problems to lift up the head and finally it becomes impossible at all. Then you can move the head without forcing the switched off motor to spin.
The solution:The tilt motor is gilty, it's too weak for the head, use a better one :-)
The gear within it seems to work fine though it consists of plastic parts, but the gear protector (if it is really intended to have one) does not. If the motor can not move the head (because of an obstacle such as the ground or it's own weigth), it spins, the gear works, but its end spins within the connector to the outside of the motor. That weakens this connection. Therefore the maximum torque the motor can provide to the outside gets too low to lift up the head.
The way of finding it:is described below
Remove the visir, the ears and the head pressure sensor.

Remove all skrews from the head part.

The mouth can be removed: pull it to one side and decide if it was the right one.

Pull out the connectors to the robot body by pulling on its lower side (see arrow). You may skip that.

When opening the part connected to the body it's a little tricky to handle power LED and power switch. Don't give up. There will be more challenging parts...
Remove the left eye by one skrew (see arrow).
Remove the final skrew to get to the tilt motor. It is in the white plastic part (see arrow).

Now you should be able to pull the head out of the body part.
Now it is possible to access the tilt motor.
Now you should be able to remove the tilt joint.

Remember the position of the white plastic part before and pulling the motor out and removing it from the motor.

Carefully remove one side of the connector from the motor to be able to open it.
The inner part of the motor: the complete gear and the weak gear protector (?).
This is the bad part. May be intended to protect the gear, may be simply bad quality...
The inner part can be moved too easily within the outer part.

Fix loose parts.



then you should skrew together everything in the right way...