Nellcor NPB-40 Service Manual

Technical Supplement
S-4
The NPB-40 is powered by four AA-size replaceable alkaline batteries. A dc
voltage in the range of 3.6 to 6 Vdc is provided over the life of these batteries.
When the voltage from these batteries drops to a level too low to operate the
NPB-40, the unit will shut itself off. At that time, the batteries must be
replaced.
The front panel keypad contains four keys that provide discrete signals that
are monitored by the microprocessor on the CPU PCB. Refer to Figure S4-5
for a schematic diagram of the front panel keypad.
Batteries
Front
panel
keypad
Power
control
and PCB
power
CPU
External
output
port
Power
condition
and PCB
power
LCD
Beeper
LCD
backlight
Analog
sensor
circuits
Printer
IR LED
drive
Patient
sensor
input
CPU PCB LCD PCB
External
serial
interface
External
output
control
3.6-6 Vdc
On/off key
Function
keys
Raw power
Sensor
analog
signal
and
control
Battery
voltage
sense
Printer
signal
LCD
enable
Beeper
signal
LCD
data
Backlight
control
Power
down
Figure S3-1: NPB-40 Block Diagram

Nellcor NPB-40 Specifications

General

Brand	Nellcor
Model	NPB-40
Category	Medical Equipment
Language	English