Nellcor OxiMax N-550 User manual

N-550
Pulse Oximeter
Service Manual
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SpO2
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N-550
SatSeconds
SpO2

Nellcor Puritan Bennett Inc. is an affiliate of Tyco Healthcare. Nellcor, Oxiband, Durasensor, OxiCliq,
OxiBand, Dura-Y, Max-Fast, and OXIMAX are trademarks of Nellcor Puritan Bennett Inc.
To obtain information about a warranty, if any, contact Nellcor’s Technical Services Department, or your local
representative.
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.
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; Re. 35,122; 4,802,486; 4,869,254; 4,928,692; 4,934,372; 5,078,136; 5,351,685; 5,368,026; 5,485,847;
5,533,507; 5,662,106; 5,853,364; and 6,083,172.

N-550 i
Contents
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .v
Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .vii
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Warnings ...............................................................................................................1
Cautions ................................................................................................................1
Notes ....................................................................................................................1
Manual Overview ..................................................................................................2
Description Of N-550 Pulse Oximeter ...................................................................2
Related Documents ..............................................................................................4
Routine Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Cleaning ................................................................................................................5
Periodic Safety Checks .........................................................................................5
Functional Checks ................................................................................................5
Battery ..................................................................................................................6
Performance Verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Introduction ...........................................................................................................7
Equipment Needed ...............................................................................................7
Performance Tests ...............................................................................................8
Battery Charge .........................................................................................8
Power-Up Performance ...........................................................................8
Power-On Self-Test (POST) .......................................................9
Power-On Defaults and Alarm Limit Ranges ............................12
General Operation .................................................................................16
LED Excitation Test ..................................................................16
Operation with a Live Subject ...................................................17
Alarm Volume Control ...............................................................18
Pulse Tone Volume Control ......................................................19
Pulse Oximetry Functional Tests ...........................................................19
Introduction ...............................................................................20
Initial Setup ...............................................................................21
Test #1: BPM ............................................................................22
Test #2: SpO2 ...........................................................................23
Test #3: Modulation Level .........................................................24
Test #4: Light ............................................................................25
Safety Tests ........................................................................................................27
Audible Alarm Settings and Service Functions . . . . . . . . . . . . . . . . . . . . 29
Introduction .........................................................................................................29
Audible Alarm Settings .......................................................................................29
Alarm Silence State ...............................................................................29
Alarm Silence Duration ..........................................................................30
Alarm Volume ........................................................................................30
N-550 Menu ........................................................................................................30
Operator's Menu Options ....................................................................................32

Contents
ii
Accessing Menu Items ...........................................................................33
Menu Item 1 (Trend Print) ......................................................................33
Menu Item 2 (Trend Clear) ....................................................................34
Menu Item 3 (Language Selection) ........................................................34
Menu Item 4 (Baud Rate) ......................................................................34
Menu Item 5 (EPP Mode) ......................................................................34
Service Menu Options ........................................................................................35
Menu Item 6 (In-Sensor Trend Mode) ...................................................35
Menu Item 7 (RS-232 Nurse Call Polarity) ............................................35
Menu Item 8 (Time Set) .........................................................................36
Menu Item 9 (Save Current Values as Power-On Defaults) ..................37
Menu Item 10 (Restore Factory Default Settings
as Power-On Default) ......................................................................38
Menu Item 11 (Alarm Silence Restrictions) ...........................................39
Menu Item 12 (Silence Alarms) .............................................................40
Menu Item 13 (All Display Off) ...............................................................40
Menu Item 14 (Alarm Sound Style Select) .............................................40
Setting Institutional Defaults (Sample) ................................................................41
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Introduction .........................................................................................................43
How To Use This Section ...................................................................................43
Who Should Perform Repairs .............................................................................43
Troubleshooting Guide .......................................................................................43
Power .....................................................................................................44
Buttons ...................................................................................................46
Display/Alarms .......................................................................................47
Operational Performance .......................................................................48
Data Port ................................................................................................49
Error Codes ........................................................................................................49
Disassembly Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Introduction .........................................................................................................55
Replacement Level Supported ...........................................................................56
Prior to Disassembly ...........................................................................................56
Separating Top and Bottom Cases .....................................................................56
Front Case Disassembly .....................................................................................58
MP-506 Removal ................................................................................................61
Main PCB Removal ............................................................................................62
Power Supply Removal ......................................................................................64
Fan Removal ......................................................................................................66
Battery Removal .................................................................................................68
Equipotential Terminal Removal .........................................................................69
Spare Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Introduction .........................................................................................................73
Obtaining Replacement Parts .............................................................................73
Parts List and Accessories .................................................................................73
Packing for Shipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Introduction .........................................................................................................77
Returning the N-550 ...........................................................................................77
General Instructions ............................................................................................77
Repacking in Original Carton ..............................................................................77

Contents
N-550 iii
Repacking in a Different Carton ..........................................................................79
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Performance .......................................................................................................81
Electrical .............................................................................................................82
Environmental Conditions ...................................................................................82
Physical Characteristics ......................................................................................84
Compliance .........................................................................................................85
Safety Tests ........................................................................................................87
Ground Integrity .....................................................................................87
Earth Leakage Current ..........................................................................87
Enclosure Leakage Current ...................................................................87
Patient Risk Applied Current ..................................................................88
Patient Isolation Risk Current ................................................................88
Data Port Interface Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
Introduction .........................................................................................................89
Enabling The Data Port ......................................................................................89
Protocol ..................................................................................................89
Baud Rate ..............................................................................................90
Connecting To The Data Port .............................................................................91
Nurse Call Polarity Settings ...................................................................93
Nurse Call Relay Pin States ..................................................................93
Nurse Call Relay Rating ........................................................................93
Real-Time Printout ..............................................................................................93
Column Heading ....................................................................................94
Printout Source ......................................................................................95
Software Revision Level ........................................................................95
Alarm Limits ...........................................................................................95
Column Headings ..................................................................................95
Time Tag ................................................................................................96
Patient Data ...........................................................................................96
Operating Status ....................................................................................96
Technical Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
Oximetry Overview .............................................................................................99
Automatic Calibration ...........................................................................100
Functional versus Fractional Saturation ..............................................100
Measured versus Calculated Saturation ..............................................100
SatSeconds Alarm Management ......................................................................101
Reads Through Motion .....................................................................................101
OXIMAX Technology ........................................................................................102
MP-506 Interface ..............................................................................................102
Circuit Analysis .................................................................................................104
Block Diagram Theory ......................................................................................105
AC Input ............................................................................................................105
Power Supply PCB Theory Of Operation .........................................................106
Battery ..............................................................................................................106
Main PCB ..........................................................................................................106
Regulated DC Power Supply ...............................................................107
Controlling Hardware ...........................................................................107
CPU .....................................................................................................107
Charging Circuits .................................................................................108
Real-Time Clock (RTC) .......................................................................108

Contents
iv
Storage of Patient Data .......................................................................108
Front Panel PCB and Controls .........................................................................109
Front Panel Display .............................................................................109
Button Interface ...................................................................................109
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

Contents
N-550 v
Figures
Figure 1: N-550 Front Panel ..............................................................................3
Figure 2: N-550 Rear Panel ..............................................................................3
Figure 3: N-550 Controls ...................................................................................9
Figure 4: Adjusting High %SpO2 Alarm Limit .................................................12
Figure 5: Adjusting Low %SpO2 Alarm Limit ..................................................13
Figure 6: Adjusting High Pulse Rate Alarm Limit ............................................14
Figure 7: Adjusting Low Pulse Rate Alarm Limit .............................................14
Figure 8: Adjusting SatSeconds Alarm Limit ...................................................15
Figure 9: N-550 Controls .................................................................................29
Figure 10: Year Month Display ..........................................................................36
Figure 11: Day Hour Display .............................................................................36
Figure 12: Minute Second Display ....................................................................37
Figure 13: N-550 Rear Panel Screws ...............................................................57
Figure 14: N-550 Case Screws .........................................................................57
Figure 15: Top Case Removal ..........................................................................57
Figure 16: Separated Cases .............................................................................58
Figure 17: Front case Wiring .............................................................................59
Figure 18: Front Case Mounting Screws ...........................................................59
Figure 19: Front Case Bracket ..........................................................................60
Figure 20: Speaker Removal ............................................................................60
Figure 21: Front PCB Removed ........................................................................60
Figure 22: MP-506 Cable Connections .............................................................61
Figure 23: MP-506 Removal .............................................................................62
Figure 24: Front case Wiring .............................................................................62
Figure 25: Front Case Mounting Screws ...........................................................63
Figure 26: Main PCB Removal ..........................................................................63
Figure 27: Main PCB Removed ........................................................................64
Figure 28: Power Supply Wiring ........................................................................65
Figure 29: Power Supply Screws ......................................................................65
Figure 30: Power Supply Removed ..................................................................66
Figure 31: Fan Wires .........................................................................................66
Figure 32: Fan Bracket Removal ......................................................................67
Figure 33: Fan and Bracket Removal ...............................................................67
Figure 34: Fan Screws ......................................................................................68
Figure 35: Battery Connections .........................................................................68
Figure 36: Battery Removed .............................................................................69
Figure 37: Ground Wire .....................................................................................70
Figure 38: Equipotential Ground Terminal ........................................................70
Figure 39: Equipotential Ground Terminal Removed ........................................71
Figure 40: Exploded View .................................................................................76
Figure 41: Packing ............................................................................................78
Figure 42: Data Port Pin Layout ........................................................................92
Figure 43: Real-Time Printout ...........................................................................94
Figure 44: Oxyhemoglobin Dissociation Curve ...............................................101
Figure 45: MP-506 Interface ...........................................................................103
Figure 46: Block Diagram ................................................................................105
Figure 47: Battery Charger Schematic Diagram .............................................111
Figure 48: Main PCB Isolation for MP-506 Schematic Diagram .....................113

Contents
vi
Figure 49: Main PCB Isolation for Interface Schematic Diagram ....................115
Figure 50: Main PCB DC/Battery Input and DC/DC Schematic Diagram .......117
Figure 51: Main PCB Interface and Speaker Control Schematic Diagram .....119
Figure 52: Main PCB MCU and Storage Control Schematic Diagram ............121
Figure 53: Front Panel 7-Segment Display Schematic Diagram .....................123
Figure 54: Front Panel LED Display and Buttons Schematic Diagram ...........125
Figure 55: Front Panel Interface and Drivers Schematic Diagram ..................127
Figure 56: Main PCB Parts Locator Diagram ..................................................129
Figure 57: Front Panel Parts Locator Diagram ...............................................131
Figure 58: Power Supply Parts Locator Diagram ............................................133

Contents
N-550 vii
Tables
Table 1: Equipment Needed .............................................................................7
Table 2: N-550 Menu Selections ....................................................................30
Table 3: Institutional Default Values ...............................................................37
Table 4: Factory Default Settings ...................................................................38
Table 5: Problem Categories ..........................................................................44
Table 6: Power Problems ...............................................................................45
Table 7: Button Problems ...............................................................................46
Table 8: Display/Alarms Problems ..................................................................47
Table 9: Operational Performance Problems .................................................48
Table 10: Data Port Problems ..........................................................................49
Table 11: Error Codes ......................................................................................50
Table 12: Spare Parts and Accessories ...........................................................73
Table 13: Data Port Pinouts ..............................................................................91
Table 14: Status Codes ....................................................................................97
Table 15: MP-506 J1 Pinouts .........................................................................103
Table 16: MP-506 J2 Pinouts .........................................................................104

Blank Page

N-550 1
Introduction
Warnings
Warnings are identified by the WARNING symbol shown above and a line
above and below the warning text. The word WARNING and all warning text
are boldfaced.
Warnings alert the user to potential serious outcomes (death, injury, or adverse
events) to the patient or user.
Cautions
Cautions are identified by the CAUTION symbol shown above. The word
CAUTION and the caution text are boldfaced.
Cautions alert the user to exercise care necessary for the safe and effective use
of the N-550.
Notes
Notes are identified by the Note symbol shown above.
Notes provide additional useful information.

Introduction
2
Manual Overview
This manual contains information for servicing the Nellcor®model N-550
pulse oximeter. Only qualified service personnel should service this product.
Before servicing the N-550, read the operator's manual carefully for a
thorough understanding of operation.
WARNING: Explosion hazard. Do not use the N-550 pulse oximeter in
the presence of flammable anesthetics.
Description Of N-550 Pulse Oximeter
The N-550 Pulse Oximeter is indicated for the continuous noninvasive
monitoring of functional oxygen saturation of arterial hemoglobin (SpO2) and
pulse rate. The N-550 is intended for use with neonatal, pediatric, and adult
patients during both no-motion and motion conditions and for patients who
are well or poorly perfused in hospitals, hospital-type facilities, intra-hospital
transport, and home environments. For prescription use only.
Note: Hospital use typically covers such areas as general care floors,
operating rooms, special procedure areas, intensive and critical care
areas, within the hospital plus hospital-type facilities. Hospital-type
facilities include physician office based facilities, sleep labs, skilled
nursing facilities, surgicenters, and subacute centers.
Intra-hospital transport includes transport of a patient within the
hospital or hospital-type facility.
Use with any particular patient requires the selection of an appropriate oxygen
transducer as described in the N-550 Operator's Manual.
Motion performance claims are applicable to models MAX-A, MAX-AL,
MAX-P, MAX-N, and MAX-I Nellcor OXIMAXTM oximetry sensors.
Digital displays are provided for oxygen saturation and pulse rate, and a
10-segment light-emitting diode (LED) bar indicates pulse amplitude. The
controls and indicators for the N-550 are illustrated and defined in Figure 1
and Figure 2 on page 3.

Introduction
N-550 3
Figure 1: N-550 Front Panel
Figure 2: N-550 Rear Panel
1 — SpO2Sensor Port 12 — SatSeconds Alarm Limit Button
2 — Power On/Off Button 13 — SpO2Alarm Limit Button
3 — % SpO2Display 14 — Motion Indicator
4 — Pulse Amplitude Indicator 15 — Sensor Off Indicator
5 — Pulse Rate Display 16 — Sensor Message Indicator
6 — Alarm Silence Button 17 — Pulse Search Indicator
7 — Alarm Silence Indicator 18 — Data In Sensor Indicator
8 — Adjust Up Button 19 — Low Battery Indicator
9 — Adjust Down Button 20 — AC Power Indicator
10 — Pulse Rate Alarm Limit Button 21 — Speaker
11 — SatSeconds Display
1 — Data Port Connector 3 — AC Power Connector
2 — Foot Switch Connector 4 — Equipotential Terminal

Introduction
4
Related Documents
To perform test and troubleshooting procedures and to understand the
principles of operation and circuit analysis sections of this manual, you must
know how to operate the N-550. Refer to the N-550 operator's manual. To
understand the various Nellcor sensors that work with the N-550, refer to the
individual sensor's directions for use.
The latest versions of the operator’s manual and the service manual are posted
on the Internet at:
http://www.mallinckrodt.com/respiratory/resp/Serv_Supp/ProductManuals.html
Spare parts and accessories are posted on the Internet at:
http://www.mallinckrodt.com/respiratory/resp/Serv_Supp/Apartweb/main/PartAcceMenu.html

N-550 5
Routine Maintenance
Cleaning
CAUTION: Do not spray, pour, or spill any liquid on the N-550, its
accessories, connectors, switches, or openings in the chassis.
For surface-cleaning and disinfecting follow your institution's procedures or:
• The N-550 may be surface-cleaned by using a soft cloth dampened
with either a commercial, nonabrasive cleaner or a solution of 70%
alcohol in water, and lightly wiping the surfaces of the N-550.
• The N-550 may be disinfected using a soft cloth saturated with a 10%
solution of chlorine bleach in tap water.
Before attempting to clean an SpO2sensor, read the directions for use
enclosed with the sensor. Each sensor model has cleaning instructions specific
to that sensor.
Periodic Safety Checks
The N-550 requires no routine service or calibration other than changing the
battery at least every two years. See Battery Removal on page 68. The
following checks should be performed at least every two years by a qualified
service technician.
1. Inspect the equipment for mechanical and functional damage.
2. Inspect safety labels for legibility. If the labels are damaged, contact
Nellcor’s Technical Services Department, 1.800.635.5267, or your local
Nellcor representative.
Functional Checks
1. If the N-550 has been visibly damaged or subjected to mechanical shock
(for example, if dropped), perform the performance tests. See
Performance Tests on page 8.

Routine Maintenance
6
2. Perform the electrical safety tests detailed in Safety Tests on page 27. If
the N-550 fails these electrical safety tests, refer to Troubleshooting on
page 43.
3. Inspect the fuses for proper value and rating (F1 and F2 = 2 amp,
250 volts).
Battery
Nellcor recommends replacing the N-550's battery every two years. When the
N-550 is going to be stored for two months or more, remove the battery prior
to storage. To replace or remove the battery, refer to Disassembly Guide on
page 55.
If the N-550 has been stored for more than 30 days, charge the battery as
described in Battery Charge on page 8. A fully discharged battery requires
11 hours with the N-550 in standby, or 12 hours if it is in use, to receive a full
charge. The battery is being charged whenever the N-550 is plugged into an
AC power source.

N-550 7
Performance Verification
Introduction
This section discusses the tests used to verify performance following repairs
or during routine maintenance. All tests can be performed without removing
the N-550 cover. All tests except the battery charge and battery performance
tests must be performed as the last operation before the N-550 is returned to
the user.
If the N-550 fails to perform as specified in any test, repairs must be made to
correct the problem before the N-550 is returned to the user.
Equipment Needed
Table 1: Equipment Needed
Equipment Description
Digital multimeter (DMM) Fluke Model 87 or equivalent
Durasensor®oxygen transducer
(sensor)
DS-100A
OXIMAX oxygen transducer MAX-A
Pulse oximeter tester SRC-MAX (must meet current EN
61326-1, FCC Part 15, and UL 1010-1,
or IEC 61010-1, or CSA 22.2 No.
1010-1 specifications)
Safety analyzer Must meet current AAMI ESI/1993 &
IEC 60601-1/1998 specifications
Pulse oximetry cable DOC-10
Data interface cable EIA-232 cable (optional)
Stopwatch Manual or electronic

Performance Verification
8
Performance Tests
Note: This section is written using Nellcor factory-set defaults. If your
institution has preconfigured custom defaults, those values will be
displayed. Factory defaults can be restored. See Menu Item 10
(Restore Factory Default Settings as Power-On Default) on page 38.
The battery should be charged before the N-550 is repaired.
Battery Charge
Perform the following procedure to fully charge the battery.
1. Connect the N-550 to an AC power source.
2. Verify that the N-550 is off and that the AC Power/Battery Charging
indicator is lit.
3. Charge the battery for at least 11 hours in standby.
Power-Up Performance
The power-up performance tests verify the following N-550 functions:
•Power-On Self-Test (POST) on page 9
•Power-On Defaults and Alarm Limit Ranges on page 12

Performance Verification
N-550 9
Figure 3: N-550 Controls
Power-On Self-Test (POST)
CAUTION: If any indicator or display element does not light, or the
speaker does not sound, do not use the N-550. Instead, contact qualified
service personnel, your local Nellcor representative, or Nellcor's
Technical Services Department, 1.800.635.5267.
Note: The N-550 should complete the POST function within 12 seconds.
1. Turn on the N-550 by pressing the Power On/Off button for greater than
0.5 seconds.
2. The N-550 displays/sounds:
1 — Power On/Off Button 5 — Pulse Rate Alarm Limit Button
2 — Alarm Silence Button 6 — SatSeconds Alarm Limit Button
3 — Adjust Up Button 7 — SpO2Alarm Limit Button
4 — Adjust Down Button
Display Sound
5 (in pulse rate left window) low priority alarm
5 (in pulse rate center window) medium priority alarm
0 (in pulse rate right window) high priority alarm
n (in SpO2left window)
n (in SpO2center window)

Performance Verification
10
3. The N-550 automatically starts the Power-On Self-Test (POST), which
tests N-550 circuitry and functions.
CAUTION: During POST (immediately after power-up), confirm that all
display segments and indicators light, and the speaker sounds a
one-second pass tone.
4. While performing POST, the self-test display appears for approximately
five seconds. During this time:
• All indicators illuminate
• All segments of all numeric digits light and change from red to green
• All segments of the Pulse Amplitude Display light
• All segments of the SatSeconds indicator light