Erratic Or Missing Values; Fixed Error Values; Missing Display Segmenis - Nellcor N-180 Service Manual

Incorrect Readings
Section 5: Troubleshooting
Pulse oximetry values are affected by incorrect sensor use, patient physiology,
or ambient conditions. Use a Nellcor pulse oximeter tester to verify incorrect
values before attempting corrective measures.
If the monitor indicates incorrect values when a pulse oximeter tester is
connected, the problem is most likely in the monitor. Erratic and fixed error
values fluctuate outside the expected range.
Table 5-2: Erratic or Missing Values
Probable cause
Action
Defective monitor
Defective sensor connector assembly.
Defective oximetry module
Defective CPU PCB
Defective LED Drive PCB and LED
PCB assembly
Contact qualified service authority
Replace sensor connector assembly
Replace oximetry module
Replace CPU PCB
Replace assembly
Table 5-3: Fixed Error Values
PCB assembly
Probable cause Action.
Defective monitor Contact qualified service authority
Defective oximetry module Replace oximetry module
Defective CPU PCB Replace CPU PCB
Defective LED Drive PCB and LED | Replace assembly
Table 5-4: Missing Display Segments
Probable cause
Action
Defective connection between the
LED Drive and LED PCBs,
Defective LEDs on the LED PCB.
Defective display decoder and driver
ICs on the LED Drive PCB.
Defective CPU PCB
Check the connectors labeled CN on
both PCBs.
Replace LED PCB.
Replace the LED Drive PCB.
Replace the CPU PCB.