Service manual

Ultraview 1030/1050 Monitors — Service Manual
5-27
Troubleshooting
Oxygen Preamp/Analog to Digital Converter Problem
Attach a known good O
2
sensor and cable to the O
2
connector on the front panel of the module. If
a signal is measured between TP10 and TP2 of the CO
2
/SDLC PCBA, but no O
2
is displayed,
then replace the CO
2
/SDLC PCBA.
Flex Circuit Problem (for Option G only)
Attach a known good O
2
sensor and cable to the O
2
connector on the front panel of the module.
Connect the DVM to TP10 and TP2 (isolated ground) on the CO
2
/SDLD PCBA. The signal should
measure 7 to 15 mV in room air. If a signal is measured at the external cable but not at TP10,
replace the flex circuit.
O
2
Reads Low
O
2
Span Required
Perform a room O
2
span and a 100% O
2
span.
Weak O
2
Sensor
Plug one end of a known good O
2
cable into the O
2
sensor connector and measure the voltage
between the tip and sleeve of the cable on the other end.
The sensor should produce 7 to 15 mV in room air. Replace the O
2
sensor if it is less than 7 mV.
Oxygen Preamp/Analog to Digital Converter Problem
Attach a known good O
2
sensor and cable to the O
2
connector on the front panel of the module.
If 7 to 15 mV is measured between TP10 and TP2 of the CO
2
/SDLC PCBA, but very low O
2
is
displayed, replace the CO
2
/SDLC PCBA. Replace the O
2
sensor if it is less than 7 mV.
Note:
If the O
2
reads correctly at room air but is low at 100% O
2
, perform a 100% O
2
span. If this
does not work, the sensor is weak and needs to be replaced. With normal use, the cell should
last for about one year, but if it is used extensively at high concentrations of oxygen, it may
become exhausted sooner.
CO
2
Check Reads Low
Refer to Calibration on page 4-8 for more information.
• Try an alternate gas bottle and repeat the check procedure.
• Verify that the barometric pressure value is correct. If it is not, replace the sensor interface
PCBA.
• Replace the CO
2
sensor.
• Replace the Sensor Interface PCBA.