Datex-Ohmeda 7900 Service Manual page 48

4/Tests and Troubleshooting
If the calibration of the manifold sensor fails on power up, an alarm occurs and is
displayed appropriately "Manifold Pressure Sensor Failure". An error code (1003E)
will also register on the error code service mode menu.
*If one or more of these tests fail, the display provides a readout which tells the op-
erator to contact an Ohmeda Service Representative.
These tests are run continuously during normal operation and alarms are associ-
ated with each test. A failure causes an alarm to display on the screen in the alarm
display area. See section 4.7 of this chapter and the Appendix in the O&M Manual.
• Flow valve electrical feedback
• Gas inlet valve electrical feedback
• Supply voltage checks
• Battery voltage checks
These tests are run periodically (every 30 seconds) during normal operation and
alarms are associated with each test. A failure causes an alarm to display on the
screen in the alarm display area. See section 4.7 of this chapter and the Appendix
in the O&M Manual.
• CPU Test
• Display RAM walking pattern test
• Data RAM walking pattern test
• FLASH ROM CRC verification
This test runs only at boot up when mechanical ventilation is turned off:
• Gas inlet valve (electrical and pneumatic)
If the gas inlet valve fails on power up, an alarm occurs and is displayed appropri-
ately "Gas Inlet Valve Circuit Failure" Also an error code (1002C) will register on
the error code service mode menu.
If the self test has passed, the remainder of the service troubleshooting is checking
the system visually and running the tests from the Service Mode Menu.
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