Keypad; Backlight; Cpu And Flash; Real-Time Clock - Nellcor OxiMax NPB-40 Service Manual

Technical Discussion

Keypad

Backlight

CPU and Flash

Real-Time Clock

Audio

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The user interface PCB keypad contains seven push buttons. These buttons allow
the user to setup and control of the NPB-40. The buttons are:
1 — Alarm Silence
2 — Down Arrow
3 — Data
4 — Menu
The signals from the buttons pass directly through the SpO
to the user interface PCB CPU. The Power button signal is applied to the SpO
power supply turning the NPB-40 on or off.
The backlight illuminates the display for better viewing.
The CPU controls all functions and timing for the NPB-40. The CPU
communicates with the SpO
are sent to the CPU for processing. The CPU sends signals to the patient sensor
via the patient interface for controlling the sensor light levels.
The real-time clock and non-volatile random access memory (RAM) chip
maintain time and date used in the NPB-40. These circuits utilize a gold
electrolytic super-capacitor for power when the NPB-40 is turned off.
The audio circuit drives a transducer to provide the NPB-40 tones.
5 — Backlight
6 — Up Arrow
7 — Power
PCB patient interface. The patient interface signal
2
PCB and are applied
2
2