Keypad; Backlight; Cpu And Flash; Real-Time Clock - Nellcor OxiMax N-65 Service Manual

Technical Discussion
86

Keypad

The user interface PCB keypad contains seven push buttons. These buttons allow
the user to setup and control of the monitor. 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 monitor on or off.

Backlight

The backlight illuminates the display for better viewing.

CPU and Flash

The CPU controls all functions and timing for the monitor. 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.

Real-Time Clock

The real-time clock and non-volatile random access memory (RAM) chip
maintain time and date used in the monitor. These circuits utilize a gold
electrolytic super-capacitor for power when the monitor is turned off.

Audio

The audio circuit drives a transducer to provide the monitor tones.
5 — Backlight
6 — Up Arrow
7 — Power
PCB patient interface. The patient interface signal
2
PCB and are applied
2
2
O M N-65 Service Manual
XI AX