E300: Unexpected activation of zero position sensor on secondary CEPH collimator /
E301: Timeout of zero position sensor on secondary CEPH collimator /
E302: Zero position sensor for secondary CEPH collimator never active /
E303: Zero position sensor for secondary CEPH collimator always active

The X-ray beam coming out from the tube head assembly is collimated to
the area under exam by a secondary collimator that is moving
synchronously with the CEPH sensor holder; this collimator is moved by
a stepper motor M7.

All the above messages refer to this mechanism; all the considerations
above described for E280 to E283 for patient’s collision.
In case of absence of collision between the secondary collimator and the
patient, the cause can be a fault on motor M7 and/or optical sensor
barrier B11.

• Check that during the power on phase there are movements on these
axes; 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 or the cable connecting it to the main CPU (A5). Check
that the cables between the motor M7 and X4 of board A12 is well
inserted, as for the cable X1-X2 of A12 to X23, X24 and X34 of the
main CPU.

• Check continuity of the above cables, from M7 to X4 board A12 and
from X1-2 of A12 up to X23, X24 and X34 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 B11, 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 cable X3 on A12 board and
from X1-2 of the board up to X23, X24 and X34 of the main CPU;
check continuity of the interested wires and replace the faulty one (if
any).

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