GE Corometrics 126, Service Manual

Page: 310 / 440

10-12 120 Series Maternal/Fetal Monitor Revision B
2015590-001
Strip Chart Recorder Servicing: Field Serviceable Assemblies
Paper-Low/Paper-Out Photosensor
Although these two reflective-sensors may be replaced in the field, tight tolerance
repositioning is required to ensure that the sensors function properly. Therefore, it is
recommended that the photosensors be replaced by a GE Service Representative. If
the replacement is done locally, it must be done according to the following
procedure.
NOTE:
When facing the front of the monitor: the paper-low sensor is on the right
side; the paper-out sensor is on the left side.
Removing the Paper-Low/Paper-Out Photosensor
Use the following procedure for removing the paper-low or paper-out photosensor.
1. Turn off the 120 Series Monitor and disconnect the power cord from the
monitor.
2. Remove the nine screws which secure the monitor top cover. Four screws are
located on the bottom of the monitor and five are located in the back.
3. Remove the cover by sliding it toward the rear of the monitor.
4. Disconnect the respective sensor cable from the black sensor housing. Record
the orientation of the connector for replacement later.
5. Using an allen wrench, remove the two socket-head screws which attach the
black sensor housing to the angle bracket.
6. Discard the sensor and housing.
Replacing the Paper-Low/Paper-Out Photosensor
Use the following procedure for replacing the paper-low or paper-out photosensor:
1. Attach the sensor and housing to the printhead support bracket using the two
socket-head screws. Ensure that the black sensor housing is parallel with the
top of the printhead bracket before tightening the screws.
2. Re-connect the sensor cable using the correct orientation.
3. Adjust the respective sensor as described next in this section.
4. Replace the monitor top cover and secure with all nine screws.
Adjusting the Paper-Low Photosensor
1. Load paper in the recorder. Ensure that there are no black squares showing to
indicate a paper-low condition.
2. If you haven’t already, re-connect the power cord and turn on the monitor.
3. Press the Record button to turn on the recorder. Allow the paper to advance for
a few seconds in order to tension the paper.
4. Turn off the recorder.
5. Using a digital voltmeter, connect the positive lead to J9 (pin 4) on the Recorder
Board; connect the negative lead to J9 (pin 2).
6. Adjust R31 for a reading of +150 mVdc ± 2 mVdc on the digital voltmeter.