Nellcor OxiMax N-550, Service Manual

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Technical Discussion
N-550 105
Block Diagram Theory
Figure 46: Block Diagram
The N-550 functional block diagram is shown in Figure 46. Most of the
functions of the N-550 are performed on the Main PCB. Functions on the
Main PCB include the SpO
2
module, MCU, and Memory. Other key
components of the N-550 are the Power Supply, the Front Panel PCB.
Contained on the Front Panel are annunciators and push buttons, allowing the
user to access information and to select various available parameters. The
Front Panel PCB contains SpO2, heart rate, and pulse amplitude indicator
LEDs and
SatSeconds Display LEDs. Their associated driver circuits are
included in the Main PCB.
AC Input
The N-550 allows the user to connect the N-550 to AC power ranging from
100 volts AC to 240 volts AC.
AC power enters directly the N-550’s Power Supply. A 2-amp fuse protects
both the “Line” and “Neutral” lines. These user-non accessible fuses are
located in a fuse drawer, which is part of the Power Supply located in the
N-550.