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N-180 Pulse Oximeter Service Manual

5-4

5-2

5-3

5-4

5-5

5-6

5-7

5-8

5-9

5-10

5-11

Erratic
values

Fixed error
values

Intermittently
lighted

Partially
lighted

Incorrect
values

Missing
segments

Incorrectly
lighted
indicator

Indicators
not lighted

Missing all displays
or indications

Missing one or more
displays or indicators

Incorrect
readings

Incorrect
backlighted
message
indicators

Missing display

Incorrect
display

Symptoms

Use table listed below

No audio when
power is applied

Normal
audio

Battery

28018A/15-1

Figure 5-1: Display Troubleshooting Decision Tree (1 of 4)

Summary of Contents for N-180

Page 1: ...rning This is an example of a warning This is an example of a warning Caution A caution precedes an action that may result in damage to or malfunction of the monitor Cautions are highlighted in boldfa...

Page 2: ...that work with the monitor refer to the Nellcor poster Pulse Oximetry or to the information supplied with your individual sensors CONVENTIONS USED IN THIS MANUAL The following conventions are used in...

Page 3: ...s that is tissue bone venous blood are eliminated Red absorption and infrared absorption that are at tributable to the pulsatile arterial blood are thus made distinct AUTOMATIC CALIBRATION Because lig...

Page 4: ...value may differ from mea sured SpO2 This is because the calculated saturation may not have been cor rected for the effects of variables that shift the relationship between PaO2 and saturation figure...

Page 5: ...ents figure FOG 1 include Standard original equipment manufacturer OEM oximetry module SOOM model MP 203 oximetry module For ease of reference this module is hereafter referred to as the oximetry modu...

Page 6: ...cor sensors operate An oxygen saturation signal is obtained from a Nellcor oxygen transducer at the selected patient measurement site such as a finger nose or toe Sensor LEDs generate alternate infrar...

Page 7: ...the following Processor Circuits Power Oximetry module operations are controlled by an 80C552 micro controller supported by 512K electrically programmable read only memory EPROM and 256K random access...

Page 8: ...in top down order Each monitor PCB has an associated circuit analysis paragraph in this section Oximetry Module The oximetry module is a self contained assembly that provides oxygen transducer power c...

Page 9: ...nd 15 a four phase LED drive signal with a frequency of 2710 6 Hz is created A negative LED drive bias voltage applied to R2 ensures that the output of the LED driver U3A is zero during the times when...

Page 10: ...the drive level from U3A and Q6 is turned on The resulting current flow is from Vcc through Q1 red LED Q4 and R1 to ground The LED back to back configuration ensures that the proper LED lights LED in...

Page 11: ...ximeter module tester pocket tester is connected to the module input in place of a normal patient sensor This establishes a reproducible set of values for discussion and comparison The PT 2500 conditi...

Page 12: ...oing negative U7 monitors the negative excursion of the SAT signal Device U7A is a negative peak detector that produces a DC output proportional to the maximum negative excursion of the SAT signal pul...

Page 13: ...al exceed 10 volt indicating excessive amplifier gain the microprocessor which is monitoring the output of U7B COMPARE2 acts to reduce the programmable stage gain The microprocessor controls U10B via...

Page 14: ...s 3 and 4 of the 2710 6 Hz saturation signal follow one another on the signal line the microprocessor strobes U15B twice The first strobe pulse comes 114 microseconds after the beginning of phase 3 an...

Page 15: ...ertz and a total gain of about four The filter cannot track the high frequency LED pulse input but does respond to the low frequency patient pulse modulation reproducing the patient s pulse waveform a...

Page 16: ...U4A and the current direction applied to the sensor LEDs SATIN from micro controller output CMSR3 SATIN controls the inverting amplifier through U10B and U14A Analog to Digital Conversion Analog to d...

Page 17: ...There are two data signals RXD TXD and three control signals at the module connection to the CPU PCB CTS clear to send is a logic signal active low transmitted to the oximetry module by the monitor to...

Page 18: ...is derived from the CPU PCB Volts Tolerance Current maximum ma 5 5 78 05 15 5 8 21 15 5 7 5 6 5 5 29 Clock and Timing I O P0 0 7 Address and Data Lines Chip Reference and Supply Voltage Inputs Microco...

Page 19: ...by rotating the front panel control knob Back panel switch SW1 Back panel switch SWI is a dual in line package DIP switch Switch settings control communications baud rate and the communications forma...

Page 20: ...T_THRESH the logic is conditioned by the low battery state to start flashing the LOW BATT light Low Battery Shutdown To protect the battery from excessive discharge the processor starts a 5 minute tim...

Page 21: ...oving power from the monitor The circuit conditions are now as they were in the standby condition Processor U9 also uses this sequence to turn off the monitor in the event of low battery In this case...

Page 22: ...so used by the battery charger circuits Diode D3 isolates the battery from VPS when AC power is used In the absence of AC power the 12 volt battery potential is coupled through D3 to supply regulator...

Page 23: ...front panel button but for obvious reasons you should only do this as an emergency measure The operator manual has specific warning information regarding Err3 conditions LED Drive PCB Note Power and...

Page 24: ...m Push Button Assembly The alarm push button assembly has five membrane switches and a flat cable The membrane switches and connecting cable are part of the monitor front panel assembly Control Knob T...

Page 25: ...on Nellcor Recommendation INTRODUCTION The only routine service required is that which is mandated by your institution and local or national agencies NELLCOR RECOMMENDATION Nellcor recommends replacin...

Page 26: ......

Page 27: ...ified as your qualified service authority If your medical facility does not have qualified service personnel contact Nellcor Operators are only authorized to replace an entire monitor REPLACEMENT LEVE...

Page 28: ...error 1 Defective monitor Contact qualified service personnel Defective data memory Replace the CPU PCB Err 2 error 2 Defective monitor Contact qualified service personnel Defective program memory Rep...

Page 29: ...he speaker 1 Rotate the control dial counterclockwise until CHE 2 is displayed 2 Press high saturation button to sound the alarm at maximum volume 3 Press low saturation button to sound the alarm at m...

Page 30: ...ents Incorrectly lighted indicator Indicators not lighted Missing all displays or indications Missing one or more displays or indicators Incorrect readings Incorrect backlighted message indicators Mis...

Page 31: ...nector assembly Replace sensor connector assembly Defective oximetry module Replace oximetry module Defective CPU PCB Replace CPU PCB Defective LED Drive PCB and LED PCB assembly Replace assembly Tabl...

Page 32: ...age indicators Missing display Incorrect display Symptoms Use table listed below No audio when power is applied Normal audio AC Battery 28018A 15 2 Figure 5 1 Display Troubleshooting Decision Tree 2 o...

Page 33: ...robable cause Action Defective monitor Contact qualified service authority Defective connection between the LED Drive and LED PCBs Check the connectors labeled CN on both PCBs Defective LEDs on the LE...

Page 34: ...lighted message indicators Missing display Incorrect display Symptoms Use table listed below No audio when power is applied Normal audio AC Battery 28018A 15 3 Figure 5 1 Display Troubleshooting Decis...

Page 35: ...C fuse Defective power transformer Replace the power transformer Defective CPU PCB Replace the CPU PCB No Audio second case The monitor is not connected to an AC power source all displays and indicato...

Page 36: ...ments Incorrectly lighted indicator Indicators not lighted Missing all displays or indications Missing one or more displays or indicators Incorrect readings Incorrect backlighted message indicators Mi...

Page 37: ...tive display components on the LED PCB Replace LED PCB Defective display decoder and driver ICs on the LED Drive PCB Replace the LED Drive PCB Defective CPU PCB Replace CPU PCB Table 5 11 Missing One...

Page 38: ...cision tree to help you pinpoint problems that occur with front panel controls This figure has two sheets 5 13 5 14 5 15 5 16 Front panel control knob offers no control Cannot turn on monitor Cannot t...

Page 39: ...5 13 the monitor is connected to an AC power source Operating the ON STDBY switch has no effect Table 5 13 Cannot Turn On Monitor AC Operation Probable cause Action The battery is discharged and the...

Page 40: ...4 5 15 Front panel control knob offers no control Cannot turn on monitor Cannot turn off monitor On Stdby Pushbuttons Front Panel Symptoms Use table listed below AC operation Battery operation 5 16 28...

Page 41: ...y Defective AC input assembly Replace the AC input assembly Defective power transformer Replace the power transformer Defective CPU PCB Replace the CPU PCB Table 5 15 Cannot Turn Off Monitor Probable...

Page 42: ...caused by the conditions listed in table 5 18 Table 5 18 Power Switch Troubleshooting Chart Symptom Probable cause Action Monitor does not charge battery Defective monitor or power cable Contact quali...

Page 43: ...RES AND PRECAUTIONS In some cases the PCBs have components on both sides Handle PCBs with care Before opening or disassembling the monitor do the following 1 Attach a grounding strap to your wrist 2 O...

Page 44: ...ew 64 4 places Bottom cover assembly 9 Handle 37 28018A 25 Figure 6 1 Exploded View of Monitor WIRING CONNECTIONS Figure 6 2 is a wiring connection diagram that you can use for reference when disassem...

Page 45: ...are on the bottom of an assembly you must perform all the steps leading to the assembly you wish to remove For example to replace the CPU PCB you must first remove the battery top shield and middle s...

Page 46: ...and speaker brackets Transformer AC inlet AC power inlet and control Top shield Oximetry module Middle shield Battery fuse CPU PCB Rear panel Battery The following battery removal steps assume you ar...

Page 47: ...g the speaker and the associated speaker brackets are obvious by inspection Top Shield You must remove the top shield to gain access to the Middle shield and oximetry module CPU PCB Battery fuse Trans...

Page 48: ...ning access to components 2 Remove top shield following instructions in this section 3 Disconnect connector on CPU PCB connector CN5 item 5 in illustration 4 Disconnect connector on CPU PCB connector...

Page 49: ...ure wire inside hole before soldering Ground wire Detail A 27957A 05 2 Figure 6 5 Transformer and AC Filter Details 9 Position replacement transformer on studs 10 Connect transformer wiring as follows...

Page 50: ...sformer bracket stud some monitors do not have a ground wire from the AC inlet assembly to the transformer stud c Lift out left side of rear panel assembly and attached AC power inlet and control asse...

Page 51: ...ld middle shield assembly onto bottom shield standoffs 4 Rotate middle shield assembly to gain some clearance and disconnect ribbon cable from oximetry module JP5 5 Lift oximetry module and middle shi...

Page 52: ...nd lug 36 Rear panel assembly Screw 45 CPU PCB 40 28018A 50 Speaker standoff 70 Figure 6 7 Bottom Shield Components Rear Panel Assembly The rear panel assembly has a left and a right member these memb...

Page 53: ...NR UL label U S only CSA label U S only Label 87 88 and rear panel 52 28018A 55 Figure 6 8 AC Power Inlet and Control Assembly 2 To remove a fuse holder insert the blade of a small screwdriver behind...

Page 54: ...lowing the instructions for gaining access to components in this section 2 Release ribbon cable retainer clip and disconnect ribbon cable assembly figure 6 10 from CN2 of CPU PCB 3 Remove front panel...

Page 55: ...10 Front Panel Assembly Components Removing Front Panel Assembly Components Replaceable components in the front panel assembly include LED Drive PCB PCB retention clip LED PCB Encoder assembly Sensor...

Page 56: ...ED PCB and LED Drive PCB together or simply remove the LED Drive PCB To remove the combination a Remove three screws holding LED PCB b Remove the mated LED PCB and the LED Drive PCB c To separate PCBs...

Page 57: ...d Feet The bail is a formed piece of wire stock that folds down to elevate the front of the monitor for easier viewing figure 6 12 The bail is held in place by tension To remove the bail and feet 1 Tu...

Page 58: ...N 180 Pulse Oximeter Service Manual 6 16 Bail 2 Foot 55 Bottom cover 9 28018A 75 Figure 6 12 Bail and Feet...

Page 59: ...UIPMENT Table 7 1 lists required test equipment The first item in the table is a special test adapter you must fabricate figure 7 1 Likewise there are two fixtures you must fabricate Table 7 1 Require...

Page 60: ...reading 1 2 3 4 5 6 7 8 9 10K Figure 7 2 RCAL Hi Test Fixture Test adapter two is constructed the same way as test adapter one except you adjust the potentiometer to 6 040 Ohms TESTING PERFORMANCE Per...

Page 61: ...ic shutdown occurs due to low battery 8 If monitor passes this test immediately recharge battery Charge battery following instructions in this section Testing Pulse Oximetry Function These functional...

Page 62: ...s to a minimum of 20 5 Press and hold HIGH RATE button Verify PULSE RATE displays an alarm limit of 140 6 Press and hold HIGH RATE button rotate control knob counter clockwise Verify PULSE RATE displa...

Page 63: ...3 Press and hold HIGH SAT button rotate control knob counterclockwise Verify OXYGEN SATURATION display reduces to a minimum of 80 4 Press and hold LOW SAT button Verify OXYGEN SATURATION displays an...

Page 64: ...ch is up 3 Place ON STDBY switch to ON and allow monitor to operate five minutes 4 Connect a Nellcor pulse oximeter tester to oximetry sensor input of monitor and verify following a The OXYGEN SATURAT...

Page 65: ...Turn control knob The number shown in the oxygen saturation display identifies one of seven zero to six visible RAM locations Concurrently the number shown in the pulse rate display is the real time v...

Page 66: ...of the D 25 with opaque material b Select RAM location five in OXYGEN SATURATION display This is the location that controls the red LED intensity The number in the PULSE RATE display is over 200 maxim...

Page 67: ...proper operation of the RCAL determination circuit when nothing is connected 4 Connect RCAL LO test resistor to sensor input The number in the PULSE RATE display must be 64 This step verifies proper o...

Page 68: ...rrectly 1 Connect monitor to a suitable AC power source 2 Set A dult Neo Alarm DIP switch on rear panel to A position switch one up 3 Place ON STDBY switch to ON 4 Connect a Nellcor pulse oximeter tes...

Page 69: ...integrity Electrical leakage Ground Integrity This test verifies the integrity of the power cord ground wire from the AC plug and connection with the monitor chassis ground 1 Set electrical safety an...

Page 70: ...r leakage indication must not exceed 10 microamps for 120 V monitors and 50 microamps for 220 V monitors These readings apply for all of the following AC power configurations when the monitor ON STDBY...

Page 71: ...Section 7 Performance and Safety Tests 7 13...

Page 72: ......

Page 73: ...pm 3 bpm Note The monitor pulse oximeter is calibrated to read oxyhemoglobin sat uration SpO2 of functional hemoglobin Significant levels of dysfunctional hemoglobins for example carboxyhemoglobin met...

Page 74: ...ut condensation Altitude 0 10 000 ft 3 048 m ELECTRICAL CHARACTERISTICS Protective Class Class I Mains supplied unit using a protective ground Degree of Protection Type BF Patient electrically isolate...

Page 75: ...tion 8 Specifications 8 3 Fuse 2 required 0 16 amp for 120 V 2 required 0 10 amp for 120 V PHYSICAL CHARACTERISTICS Dimensions 2 875 in high x 8 5 in wide x 7 in deep 73 x 216 x 178 mm Weight 6 6 lb 3...

Page 76: ......

Page 77: ...rts are listed in two tables Both tables contain the same in formation they are just organized differently for ease of reference Table 9 1 lists spare parts by part number and item number order Table...

Page 78: ...Shield N180 027654 23 Label S N N 180 027728 88 AC Inlet Assy N180 027839 1 Label U L Oximeter 051432 41 Label CSA C V 051708 39 Equal Potential Terminal 057068 86 Mp 203 PCB 079590 84 Conn Hdr R A 14...

Page 79: ...40 Label U L Oximeter 051432 41 LED Drive PCB 024105 42 LED Drive PCB Retention Clip 027094 43 LED PCB 026745 44 Front Panel Membrane Sw N180 022158 45 Middle Shield Insulator 022346 46 Middle Shield...

Page 80: ...he number listed below is the engineering support services control number SCHEMATIC LIST Use these schematics for reference when reading the circuit analysis section or troubleshooting equipment The o...

Page 81: ...10 2...

Page 82: ...data When using conversation format the monitor responds by request only At the computer or terminal transmit a single request the monitor responds by transmitting an alphanumeric string containing a...

Page 83: ...Lnnn H high rate alarm limit Hnnn O low sat alarm limit Onnn A alarm status in ASCII coded decimal Logic 1 equals alarm condition Bit 0 high rate Bit 1 low rate Bit 2 low sat Bit 3 high sat M monitor...

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