E400: Timeout of zero position sensor on Soft Tissue Filter /
E401: Zero position sensor for Soft Tissue Filter always active

The Soft Tissue Filter for cephalometric examinations is controlled by the
stepper motor. During the power on, the system checks the correctness
of the motion, sensing the activation and deactivation of the optical
sensor B9. If it is not sensed activated, the timeout message E400 is
displayed, while if it is always active, the E401 is displayed.
In both cases, the error can be generated by the loss of movement of the
stepper motor or by a fault of the sensor B9.

• Power off the system and remove the frontal cover of the tubehead
assembly.

• Check that during the power on phase there are movements on the
primary slit collimator; the normal motion is going to engage the
sensor and a reverse motion to disengage it. If no motion is observed,
the fault can be the stepper motor M6 or the cable connecting it to
the main CPU. Check that the cables between the motor M6 and X65
is well inserted, as for the cable X65 to X29 and X30 of the main CPU
A5.

• Check continuity of the above cables, from M6 to X65 and from X65
up to X29 and X30 of the main CPU A5.

• Repeat the power on sequence, verifying the motion.
If still there is no motion, replace the stepper motor and, if not fixed,
replace the CPU.
If a motion has been observed, but messages are displayed, this can be
the sensor or its wiring.

• Power off the system and try to manually disengage the sensor,
taking care of a smooth motion.

• Power on the system and check the functioning of the sensor,
measuring the DC voltage on the terminal of the sensor B9, with and
without an obstacle manually inserted. A variation of about 3.5 V
minimum should be observed. If not, replace the sensor.

• If the variation is observed and the message still continues to be
displayed, check the correct insertion of the cable from B9 in X33 of
the main CPU and the continuity of the connection.

• If all cables are OK, the fault is on the CPU, so replace it.