Nellcor N-40 Service manual
SERVICE MANUAL
NPB-40
Handheld Pulse Oximeter
Caution: Federal law (U.S.) restricts this device to sale by or on the order of a physician.
To contact Nellcor Puritan Bennett’s representative: In the United States, call 1-800-635-5267 or
925-463-4000; outside of the United States, call your local Nellcor Puritan Bennett representative.
© 2001 Nellcor Puritan Bennett, Inc. All rights reserved. 036048D-0601
0123
Nellcor Puritan Bennett Inc.
4280 Hacienda Drive
Pleasanton, CA 94588 USA
Telephone Toll Free 1.800.NELLCOR
Tyco Healthcare UK LTD
Fareham Road
Gosport
PO13 0AS
U.K.
Tel: +44.1329.224000
To obtain information about a warranty, if any, for this product, contact Nellcor
Puritan Bennett Technical Services Department, or your local Nellcor Puritan
Bennett representative.
Notice: Purchase of this instrument confers no express or implied license under any
Nellcor Puritan Bennett patent to use the instrument with any sensor that is not
manufactured or licensed by Nellcor Puritan Bennett.
Oxisensor II is a trademark of Nellcor Puritan Bennett, Inc.
Covered by one or more of the following U.S. Patents and foreign equivalents:
4,621,643; 4,653,498; 4,700,708; 4,770,179; 4,869,254; 4,928,692; 4,934,372; 5,078,136;
5,351,685; 5,368,026; and Re. 35,122.
TABLE OF CONTENTS
List of Figures
List of Tables
Section 1: Introduction................................................................................. 1-1
1.1 Manual Overview............................................................................ 1-1
1.2 Equipment Description ................................ ................................ ... 1-1
Section 2: Routine Maintenance ................................................................ 2-1
2.1 Maintenance Overview ................................................................... 2-1
2.2 Battery Maintenance ...................................................................... 2-1
2.3 Cleaning ................................ ................................ ............................ 2-2
Section 3: Performance Verification .......................................................... 3-1
3.1 Performance Verification ................................................................... 3-1
Section 4: Troubleshooting ................................................................ ......... 4-1
4.1 Introduction..................................................................................... 4-1
4.2 Who Should Perform Repairs......................................................... 4-1
4.3 Repair Level Supported.................................................................. 4-1
4.4 How to Use This Section ................................ ................................ 4-1
4.5 Obtaining Replacement Parts ........................................................ 4-1
4.6 Troubleshooting Guide ................................................................... 4-2
Section 5: Disassembly Guide .................................................................... 5-1
5.1 Introduction..................................................................................... 5-1
5.2 System Disassembly and Reassembly .......................................... 5-1
Section 6: Spare Parts.................................................................................. 6-1
6.1 Introduction..................................................................................... 6-1
Section 7: Packing for Shipment................................................................. 7-1
7.1 General Instructions........................................................................ 7-1
7.2 Packing NPB-40 in Original Carton ................................ ................ 7-1
7.3 Packing in a Different Carton ......................................................... 7-1
Section 8: Specifications ................................................................ ............. 8-1
8.1 Performance ................................................................................... 8-1
8.2 Electrical ......................................................................................... 8-2
8.3 Environmental................................................................................. 8-2
8.4 Physical ......................................................................................... 8-3
Technical Supplement.................................................................................. S-1
S1 Introduction..................................................................................... S-1
S2 Pulse Oximetry Principles of Operation .......................................... S-1
S3 Circuit Analysis ............................................................................... S-2
S4 Schematic Diagrams ................................ ................................ ...... S-17
2.2.1 Battery Replacement ......................................................... 2-1
2.2.2 Battery Disposal ................................................................ 2-2
S2.1 Overview ................................................................ ........... S-1
S2.2 Functional Versus Fractional Saturation............................ S-1
S2.3 Measured versus Calculated Saturation............................ S-2
S3.1 Overall Unit Block Diagram Analysis ................................ . S-3
S3.2 CPU PCB Theory of Operation.......................................... S-5
S3.3 LCD PCB Theory of Operation .......................................... S-11
iii
Table of Contents
LIST OF FIGURES
1-1 NPB-40 Handheld Pulse Oximeter ................................................ 1-1
1-2 NPB-40 Front Panel....................................................................... 1-2
2-1 NPB-40 Battery Installation ........................................................... 2-2
3-1 NPB-40 Self-Test Front Panel Display ................................ .......... 3-1
3-2 Printer Interface Setup................................................................... 3-3
3-3 Typical Average Data Print Out ..................................................... 3-4
3-4 Typical Data Print Out ................................................................... 3-5
4-1 Typical Error Code Display ............................................................ 4-2
5-1 Opening the NPB-40 Case ............................................................ 5-2
5-2 Top Case Removal ........................................................................ 5-2
5-3 Unlocking CPU PCB Connector J3 ............................................... 5-3
5-4 Separating LCD PCB from CPU PCB............................................ 5-3
6-1 NPB-40 Expanded View ................................................................ 6-2
7-1 Repacking the NPB-40 .................................................................. 7-2
S2-1 Oxyhemoglobin Dissociation Curve .............................................. S-2
S3-1 NPB-40 Block Diagram ................................................................. S-4
S3-2 CPU PCB Block Diagram .............................................................. S-6
S3-3 LCD PCB Block Diagram............................................................... S-12
S4-1 CPU PCB Parts Locator Diagram.................................................. FO-1
S4-2 LCD PCB Parts Locator Diagram .................................................. FO-2
S4-3 CPU PCB Schematic Diagram ...................................................... FO-3
S4-4 LCD PCB Schematic Diagram....................................................... FO-4
S4-5 Front Panel Keypad Schematic Diagram ...................................... FO-5
LIST OF TABLES
4-1 Troubleshooting Guide .................................................................. 4-2
4-2 NPB-40 Error Codes ..................................................................... 4-5
iv
SECTION 1: INTRODUCTION
1.1 Manual Overview
1.2 Equipment Description
1.1 MANUAL OVERVIEW
This manual contains information for servicing the NPB-40 handheld pulse
oximeter. Only qualified service personnel should service this product. Before
servicing the NPB-40, read the operator’s manual carefully for a thorough
understanding of how to operate the NPB-40.
1.2 EQUIPMENT DESCRIPTION
The Nellcor Puritan Bennett NPB-40 handheld pulse oximeter is used for
noninvasive spot-check measurement of functional oxygen saturation of
arterial hemoglobin (SpO2) and pulse rate (measured by the SpO2 sensor).
The NPB-40 is for attended monitoring only, and must be used in the
continuous presence of a qualified healthcare provider. The NPB-40 can be
used on adult, pediatric, and neonatal patients. It can be used in mobile
environments when protected from excessive moisture such as direct rainfall.
The NPB-40 is powered by four “AA” cell alkaline batteries. An external
Hewlett-Packard HP82240B printer can be used with the NPB-40 to printout
readings stored in the NPB-40 memory. This printer is available from Nellcor
Puritan Bennett. The NPB-40 handheld pulse oximeter is illustrated in
Figure 1-1.
Figure 1-1: NPB-40 Handheld Pulse Oximeter
The NPB-40 is operated using a four-key keypad and an LCD display on the
front panel as shown in Figure 1-2. Refer to the NPB-40 operator’s manual
for complete operating instructions.
1-1
Section 1: Introduction
13
12
11
10
1
Pulse Amplitude indicator
2
1
2
3
4
5
9
8
6
7
Pulse Rate display
3
Pulse Search display
4
Low Battery indicator
5
Sensor disconnect indicator
6
Power On/Off key
7
Display Light/Beep On/Off key
8
Store Data/Print key
9
Shift key
10
Store Data icon
11
Shift icon
12
Print icon
13
SpO2% display
Figure 1-2: NPB-40 Front Panel
1-2
SECTION 2: ROUTINE MAINTENANCE
2.1 Maintenance Overview
2.2 Battery Maintenance
2.3 Cleaning
2.1 MAINTENANCE OVERVIEW
The NPB-40 requires no routine service or calibration. The performance
verification tests in Section 3, Performance Verification, may be used
following repairs or during routine maintenance (if required by your local
institution).
2.2 BATTERY MAINTENANCE
Warning: The NPB-40 uses four “AA” cell alkaline batteries for
operation. If batteries are not replaced when recommended or are
not disposed of properly, serious personal injury or damage to the
NPB-40 could result.
Caution: When inserting the positive end of each battery, exercise
caution to not damage the small coiled spring contact.
Nellcor Puritan Bennett recommends that you comply with the following
guidelines for battery replacement and battery disposal as a minimum.
2.2.1 Battery Replacement
Caution: The NPB-40 could be damaged by batteries that are left
unused in the unit and begin to leak. Never store the NPB-40 with
the batteries installed for a prolonged period of time.
NPB-40 batteries should be replaced whenever a low battery indication is
observed on the unit. Remove the batteries if you will be storing the NPB-40
for longer than one month. Refer Figure 2-1 for replacing the batteries.
Note: For easier battery installation, insert the negative end of the battery
first when installing each battery.
2-1
Section 2: Routine Maintenance
2.2.2 Battery Disposal
2.3 CLEANING
Figure 2-1: NPB-40 Battery Installation
When NPB-40 batteries have been replaced, dispose of the old batteries.
Always follow local ordinances when disposing of the NPB-40 batteries.
Warning: Never dispose of NPB-40 batteries by burning. The
batteries could explode in fire and cause serious personal injury.
Caution: Do not immerse the NPB-40 or accessories in liquid or use
caustic or abrasive cleaners.
To clean the NPB-40, dampen a soft cloth with a commercial nonabrasive
cleaner and wipe the unit with the cloth.
2-2
SECTION 3: PERFORMANCE VERIFICATION
3.1 Performance Verification
3.1 PERFORMANCE VERIFICATION
The performance of the NPB-40 can be verified using the following procedure.
Before performing this procedure, the NPB-40 must have fresh batteries
installed. If any of the required observations cannot be obtained, do not
return the NPB-40 to service before referring to Section 4, Troubleshooting.
You will need an SRC-2 pulse oximeter tester to perform this procedure. If
the performance of the printing function will be verified, you will need an
HP82240B printer.
The NPB-40 is to be turned off and any sensors disconnected before
performing this procedure.
1. Press the On/Off key on the front panel keypad.
2. The NPB-40 will perform a self-test. Verify that all display segments
are lit during the self-test as shown in Figure 3-1. Also verify that a low
pitched audio tone is heard at the end of the self test. Also verify that
you then hear a high, a low, and a high pitch error tone indicating that
a sensor is not connected. Verify that dashes are shown on the display
and the SENSOR DISCONNECT indicator is flashing.
Figure 3-1: NPB-40 Self-Test Front Panel Display
3. Wait for 20 to 40 seconds. Verify that two triple beeps are heard. Verify
that the NPB-40 then shuts itself off.
4. Connect an SRC-2 pulse oximeter tester to the NPB-40 sensor
connector.
Note: If the SRC-2 is connected directly to the NPB-40 sensor
connector, its controls will be facing the opposite direction of
the NPB-40 controls. Connecting the SRC-2 through a sensor
extension cable, such as the Nellcor Puritan Bennett model EC4 or EC-8, will make it easier to perform this procedure.
3-1
Section 3: Performance Verification
Set the SRC-2 controls as follows:
RATE 112
LIGHT HIGH 1
MODULATION HIGH
LOCAL/REMOTE/RCAL LOCAL
5. Press the On/Off key on the NPB-40 front panel keypad.
6. When the self-test is complete, verify that the PULSE SEARCH
indicator illuminates momentarily and verify that the NPB-40 is
displaying a pulse rate of 112 (±3 bpm), that the pulse amplitude
indicator is displaying properly, that the SpO2% indicator is displaying
81 (±2 %), that a pulse beep can be heard, and that the PULSE
SEARCH indicator is off.
7. Set the following SRC-2 controls as indicated:
RATE 38
LIGHT HIGH 2
MODULATION LOW
Wait 30 seconds and verify that the NPB-40 is displaying a pulse rate of
38 (±3 bpm), that the pulse amplitude indicator is displaying properly,
that the SpO2% indicator is displaying 81 (±2 %), that a pulse beep can
be heard, and that the PULSE SEARCH indicator is off.
8. Set the following SRC-2 controls as indicated:
RATE 201
LIGHT LOW
Wait 30 seconds and verify that the NPB-40 is displaying a pulse rate of
201 (±3 bpm), that the pulse amplitude indicator is displaying properly,
that the SpO2% indicator is displaying 81 (±2 %), that a pulse beep can
be heard, and that the PULSE SEARCH indicator is off.
9. Set the following SRC-2 control as indicated:
MODULATION HIGH
Wait 30 seconds and verify that the NPB-40 is displaying a pulse rate of
201 (±3 bpm), that the pulse amplitude indicator is displaying properly,
that the SpO2% indicator is displaying 81 (±2 %), that a pulse beep can
be heard, and that the PULSE SEARCH indicator is off.
10. Press the Shift key followed by the Display Light/Beep On/Off key.
Verify that the SHIFT indicator illuminates when the Shift key is
pressed then verify that the pulse beep stops and the SHIFT indicator
extinguishes when the Display Light/Beep On/Off key is pressed.
11. Press the Shift key followed by the Display Light/Beep On/Off key and
verify that the pulse beep can be heard again at a low level.
3-2
Section 3: Performance Verification
12. Press the Shift key followed by the Display Light/Beep On/Off key and
verify that the pulse beep can again be heard again at a higher level.
13. Press and release the Display Light/Beep On/Off key on the front panel
keypad and verify that the LCD backlight comes on, remains on and the
LCD is adequately illuminated.
14. Press the Display Light/Beep On/Off key on the front panel keypad and
verify that the LCD backlight is off.
15. Set the following SRC-2 control as indicated:
LOCAL/REMOTE/RCAL REMOTE
16. On the NPB-40, verify that the PULSE SEARCH indicator illuminates
after a few seconds and that the number “0” is displayed in the SpO2%
and pulse rate displays.
17. Set the following SRC-2 control as indicated:
LOCAL/REMOTE/RCAL LOCAL
18. On the NPB-40, verify that the PULSE SEARCH indicator illuminates
momentarily and verify that the NPB-40 is displaying a pulse rate of
201 (±3 bpm), that the pulse amplitude indicator is displaying properly,
that the SpO2% indicator is displaying 79 to 83, that a pulse beep can
be heard, and that the PULSE SEARCH indicator is off.
Note: If an HP82240B printer is not available, skip steps 19 through
27 and proceed to step 28.
19. Refer to the printer operator’s manual as needed. Verify that paper is
properly installed in the printer and turn the printer on.
20. Align the NPB-40 with the printer as shown in Figure 3-2.
0°–5°
0°–5°
1"–2" (2.5–5.1 cm.)
Figure 3-2: Printer Interface Setup
3-3
Section 3: Performance Verification
21. On the NPB-40, press the Shift key followed by the Store Data/Print
key on the front panel keypad.
Note: In the following steps, printed SpO2% values will be 79 to 83
22. Verify that the PRINT icon is illuminated on the NPB-40 display, that
the printer begins printing and that the printer prints out a summary
report similar to that shown in Figure 3-3.
and pulse rate values will be 201, ±3 bpm. Figures 3-3 and 3-4
are examples of typical print outs. The NPB-40 will not display
pulse or SpO2% values while printing.
Figure 3-3: Typical Average Data Print Out
23. With the SRC-2 connected to the NPB-40 and still set up as in step 18,
press only the Store Data/Print key on the front panel keypad and
verify that the LCD display indicates “1-Id” and the STORE DATA icon
illuminates.
24. Press only the Store Data/Print key on the front panel keypad and
verify that the LCD display indicates “2-Id” and the STORE DATA icon
illuminates.
25. Press only the Store Data/Print key on the front panel keypad and
verify that the LCD display indicates “3-Id” and the STORE DATA icon
illuminates.
26. Align the NPB-40 with the printer as shown in Figure 3-2 and press the
Shift key on the NPB-40 front panel keypad, followed by the Store
Data/Print key.
27. Verify that the PRINT icon is illuminated on the NPB-40 display, that
the printer begins printing and that the printer prints out data similar
to that shown in Figure 3-4. As data stored in steps 24, 25, and 26 is
printed out, the NPB-40 display will indicate “1-Id”, “2-Id”, and “3-Id”,
respectively.
3-4
Section 3: Performance Verification
Figure 3-4: Typical Data Print Out
28. Press the On/Off key on the front panel keypad.
29. Verify that the NPB-40 shuts off.
3-5
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SECTION 4: TROUBLESHOOTING
4.1 Introduction
4.2 Who Should Perform Repairs
4.3 Repair Level Supported
4.4 How to Use This Section
4.5 Obtaining Replacement Parts
4.6 Troubleshooting Guide
4.1 INTRODUCTION
This section provides information for troubleshooting the NPB-40 and helping
you to isolate a failure to the front panel keypad, the CPU PCB, or the LCD
PCB. A troubleshooting guide is provided in Paragraph 4.6, “Troubleshooting
Guide” that lists possible difficulties, along with probable causes, and
recommended actions to correct each difficulty. The Technical Supplement at
the end of this manual provides information on how the components of the
NPB-40 function.
4.2 WHO SHOULD PERFORM REPAIRS
Only qualified service personnel should remove and replace components of
the NPB-40. Repairs to the NPB-40 are limited to the repair level identified
in Paragraph 4.3, “Repair Level Supported.” If your facility does not have
qualified service personnel, contact the Nellcor Puritan Bennett Technical
Services Department or your local Nellcor Puritan Bennett representative.
4.3 REPAIR LEVEL SUPPORTED
Besides the batteries, the NPB-40 has five replaceable components, the case
top with the front panel keypad, the case bottom, the CPU PCB, the LCD
PCB, and the battery compartment door.
4.4 HOW TO USE THIS SECTION
Failures of the case bottom, the battery compartment door, and the case top,
not including the front panel keypad, are determined by visually inspecting
these components for cracks or deformations and for mechanical failures such
as the screw holes stripping out in the case top. The case top and the front
panel keypad are replaced together. Use the troubleshooting guide provided
in Paragraph 4.6, “Troubleshooting Guide” to isolate failure to the front panel
keypad, the CPU PCB, or the LCD PCB. Once a failure has been isolated,
refer to Section 5, Disassembly Guide for instructions for removing and
replacing a component of the NPB-40.
4.5 OBTAINING REPLACEMENT PARTS
Nellcor Puritan Bennett Technical Services Department provides technical
assistance information and replacement parts. To obtain replacement parts,
contact the Nellcor Puritan Bennett Technical Services Department or your
local Nellcor Puritan Bennett representative. Refer to parts by the part
names and part numbers listed in Section 6, Spare Parts.
4-1
Section 4: Troubleshooting
4.6 TROUBLESHOOTING GUIDE
If you encounter a problem that cannot be resolved through a visual
inspection, refer to Table 4-1 which provides a list of symptoms, probable
causes, and recommended actions to take to correct the problem. It is
recommended that corrective actions be performed in the order presented.
For a symptom that is not listed in Table 4-1, contact the Nellcor Puritan
Bennett Technical Services Department or your local Nellcor Puritan Bennett
representative.
If an error code is shown on the front panel LCD display, as shown in Figure
4-1, turn the NPB-40 off and back on again. If the error code still persists,
refer to Table 4-2 for the indicated failure and corrective action.
Figure 4-1: Typical Error Code Display
Once you have performed the recommended action, reassemble the NPB-40,
refer to Section 3, Performance Verification, and conduct a performance
verification before returning the NPB-40 to service. If the symptom persists,
continue troubleshooting.
Table 4-1: Troubleshooting Guide
Symptom Probable Cause Corrective Action
The unit does not
turn on when the
On/Off key is
The batteries are
missing.
Open the battery compartment
and if batteries are missing,
install new batteries.
pressed.
The batteries are
installed incorrectly
or are backwards.
Open the battery compartment
and if batteries are not installed
correctly, remove and reinstall
the batteries.
The batteries are at
Install new batteries.
or near a voltage too
(Continued on next
page)
low for the NPB-40 to
operate.
4-2
Section 4: Troubleshooting
Table 4-1: Troubleshooting Guide (Continued)
Symptom Probable Cause Corrective Action
The unit does not
turn on when the
The sensor is
defective.
Replace the sensor.
On/Off key is
pressed.
(continued)
The front panel
keypad is defective.
Open the NPB-40, disconnect
the case top from J3 on the CPU
PCB and connect an ohmmeter
between the flex circuit
conductor for J3, pin 5 and the
conductor for J3, pin 3. Observe
a short when the On/Off key is
pressed and an open when not
pressed. If incorrect, replace
case top. If all keys function
correctly, replace CPU PCB.
Caution: Unlock J3 before
attempting to remove flex
circuit conductor.
Flex circuit between
front panel and CPU
PCB is disconnected.
A CPU PCB
component has
failed.
Inspect the flex circuit between
the front panel and the CPU
PCB and reconnect if loose.
Inspect the CPU PCB
components and circuit board
for cracking, burning, or
damage, and replace the CPU
PCB if any are found. If any
failed components are observed,
replace CPU PCB.
Replace the CPU PCB with a
known good PCB.
One or more keys
on the front panel
keypad does not
work.
The front panel
keypad is defective.
Open the NPB-40, disconnect
the case top from J3 on the CPU
PCB and connect an ohmmeter
lead to the flex circuit conductor
for J3, pin 3. Refer to the front
panel schematic diagram and
individually connect the other
ohmmeter lead to each
conductor for the other keys.
Observe a short when the key is
pressed and an open when not
pressed. If incorrect, replace
case top. If correct, replace the
CPU PCB.
Caution: Unlock J3 before
attempting to remove flex
circuit conductor.
Flex circuit between
front panel and CPU
PCB is disconnected.
A CPU PCB
component has
failed.
(Continued on next
page)
Inspect the flex circuit between
the front panel and the CPU
PCB and reconnect if loose.
Inspect the CPU PCB
components and circuit board
for cracking, burning, or damage
and replace the CPU PCB if any
are found.
4-3
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