VPAP III, VPAP III ST, VPAP III ST-A Service Manual May 2003

Manufactured by: ResMed Ltd 1 Elizabeth MacArthur Drive Bella Vista NSW 2153 Australia Tel: +61 (2) 8884 1000 or 1 800 658 189 (toll free) Fax: +61 (2) 8883 3114 Email: [email protected] ResMed Offices: ResMed Corp 14040 Danielson Street Poway CA 92064-6857 USA Tel: +1 (858) 746-2400 or 1-800-424-0737 (toll free) Fax: +1 (858) 746-2900 Email: [email protected] ResMed (UK) Ltd 65 Milton Park Abingdon Oxfordshire OX14 4RX UK Tel: +44 (1235) 862 997 Fax: +44 (1235) 831 336 Email: [email protected] ResMed Asia Pacific Ltd 97 Waterloo Road North Ryde NSW 2113 Australia Tel: +61 (2) 9886 5000 or 1 800 991 900 (toll free) Fax: +61 (2) 9889 1471 Email: [email protected] ResMed Finland Niittykatu 6 FIN 02200 Espoo Suomi Tel: +358 9 8676820 Fax: +358 9 86768222 Email: [email protected] ResMed GmbH & Co. KG Rudolfstraße 10 D-41068 Mönchengladbach Deutschland Tel: +49 (0) 2161-3521-0 (Reception), +49 (0) 180 22 22 668 (Service-Telefon; 0.06 s/Anruf), +49 (0) 180 22 66 888 (Wartungstelefon; 0.06 s/Anruf) Fax: +49 (0) 2161-3521-1499 Email: [email protected] ResMed Hong Kong Ltd Room 1714 Miramar Tower 132-134 Nathan Road Tsim Sha Tsui Hong Kong Tel: +852 2366 0707 Fax: +852 2366 4546 Email: [email protected] ResMed Japan Nihonbashi Hisamatsu Bldg. 4F 2-28-1 Nihonbashi-Hamacho Chuo-Ku, Tokyo 103-0007 Japan Tel: +81 (3) 3662 5056 Fax: +81 (3) 3662 5040 ResMed Malaysia Sdn Bhd Suite E-10-20, Plaza Mon’t Kiara No. 2, Jalan 1/70C Mon’t Kiara 50480 Kuala Lumpur Malaysia Tel: +60 3 6201 7177 Fax: +60 3 6201 2177 Email: [email protected] ResMed NZ Ltd PO Box 51-048 Pakuranga Auckland New Zealand Tel: +0800 737 633 (NZ toll free) or +64 25 737 633 Fax: +0800 737 634 (NZ toll free) or +64 9 239 0193 Email: [email protected] ResMed SA Parc de la Bandonnière 2 rue Maurice Audibert 69800 Saint-Priest France Tel: +33 (0) 4 37 251 251 Fax: +33 (0) 4 37 251 260 Email: [email protected] ResMed Singapore Pte Ltd 238A Thomson Road # 12-03/04 Novena Square Tower A Singapore 307684 Tel: +65 6284 7177 Fax: +65 6284 7787 Email: [email protected] ResMed Spain SL C/ Arturo Soria, 245 28033 Madrid España Tel: +34 (93) 590 8154 Fax: +34 (93) 590 8153 Email: [email protected] ResMed Sweden AB Industrigatan 2 S-461 37 Trollhättan Sverige Tel: +46 520 420 110 Fax: +46 520 397 15 Email: [email protected] Labhardt AG Thannerstrasse 57 CH-4054 Basel Schweiz Tel: +41 (061) 307 9711 Fax: +41 (061) 307 9722 Email: [email protected] US DESIGNATED AGENT: ResMed Corp EU AUTHORISED REPRESENTATIVE: ResMed (UK) Ltd

Internet: www.resmed.com Protected by patents: AU 697652, AU 699726, AU 713679, EP 0661071, EP 0858352, US 4944310, US 5199424, US 5522382, US 6213119, US 6240921, US 6705315. Other patents pending. Protected by design registrations: AU 147283, AU 147335, AU 147336, CH 128.709, CH 128.710, CH 128.711, CH 128.712, DE 40201723, DE 40202007, DE 40202008, DE 40202020, ES 153514, ES 153515, ES 153516, ES 153518, ES 156135, ES 156136, FR 02 1407, GB 3001791, GB 3001819, GB 3001820, GB 3001821, JP 1164087, JP 1164265, JP 1164266, JP 1164267, JP 3638613, SE 75598, SE 75599, SE 75600, SE 75715, US D467335, US D468011, US D476077, US D477868, US D487311. Other designs pending IPAP MAX, IPAP MIN, SmartStart, TiCONTROL, VPAP, Vsync and Vsync logo are trademarks of ResMed Ltd and IPAP MAX, SmartStart, and VPAP are Registered in U.S. Patent and Trademark Office. © 2005 ResMed Ltd. 248106/3 05 04

Contents 1

How to use this manual ... ...4 4

2

Introduction ... ...5 5 Intended users of this manual Nasal CPAP

5 5

Features of the VPAP III, VPAP III ST Features of the VPAP III ST-A

5 5

HumidAire 2i™ ResLink

5 5

Software changes

6

VPAP III, VPAP III ST VPAP III ST-A

3

General inspection and servicing ...7 ...7 Instructions for general inspection procedures Equipment required For VPAP III ST-A only Software buttons Function keys VPAP III and VPAP III ST keypad and LCD VPAP III ST-A keypad and LCD 1 Clean the flow generator 2 Record clinical settings 3 External examination 4 Internal examination (if necessary) 5 Replace the air filter 6 Keypad test 7 Pressure calibration test 8 Flow calibration test 9 Blower test 10 Audible alarm test 11 VPAP III ST-A alarm test (VPAP III ST-A only) 12 DC power test (VPAP III ST-A only) 13 HumidAire 2i test 14 Reload clinical settings 15 Complete the Service record results form 16 Fill out product problem report

7 7 7 8 8 8 8 9 9 10 10 11 11 11 12 12 12 12 13 13 15 15 15

4

Static Precautions ...16 ...16

5

Replacing major subassemblies ...17 ...17 Outer components of the flow generator Opening the flow generator Remove the front muffler assembly Removing the interface assembly Remove the filter Remove the top case Replacing the blower module assembly Replacing the blower inlet and outlet connectors Replacing the fuse (for VPAP III and VPAP III ST models only) Replacing the power supply (VPAP III and VPAP III ST models)

2

6 6

VPAP® III, VPAP III ST, VPAP III ST-A Service Manual

17 18 18 19 20 20 21 25 28 29

Replacing the power supply (VPAP III ST-A models) Replacing the Main PCB Installing the serial number and default settings Replacing the cable harness with switch and humidifier connector Replacing the switch (for VPAP III and VPAP III ST models only) Placing decals on replacement bottom cases Replacing interface assembly components

Closing the flow generator Replacing front muffler components The HumidAire 2i Opening the HumidAire 2i Removing components from the water chamber The water chamber lid The water chamber base

6

42 44 46 46 47 47 48

Replacement parts list ... 51 Outside cases Air filter components Interface assembly Internal components PCBs Main wiring harnesses HumidAire 2i spare parts

7

30 31 34 34 37 40 41

51 51 52 53 53 54 55

Calibration procedures ... 56 Warnings and cautions Equipment required Software calibration buttons Order of calibration procedures 1 Pressure calibration 2 Flow calibration 3 Motor noise calibration (VPAP III ST-A only)

56 56 56 57 57 58 59

8

Troubleshooting guide ... 60

9

System specifications ... 62 VPAP III, VPAP III ST VPAP III ST-A

62 63

10 Recommended maintenance schedule ... 64 Appendix A: Service request form ... 65 Appendix B: Noise reduction upgrade ... 66 Equipment required Adding foam pads to the blower assembly Fit cable tie and replace blower outlet connector

66 66 68

Appendix C: Installing the service software ... 70

Contents

3

1

How to use this manual Each of the sections in this manual has been written with a specific purpose in mind. Use this guide to help you find the material which is relevant to your task at the moment. 2 Introduction – Gives a brief overview of the VPAP III family of flow generators. 3 General inspection and servicing – Gives a procedure to help you examine a flow generator which has been brought into a service centre. The general inspection procedures should be performed before any other work is done on the flow generator. 4 Static precautions – Lists procedures to be followed whenever PCBs are removed from the flow generator unit. These procedures minimize the chance of ICs being damaged by static electricity. 5 Replacing major subassemblies – Highlights points to note when replacing subassemblies, reassembling the flow generator and indications of when recalibration is necessary. 6 Replacement parts – Shows labelled pictures and part numbers of all the spare parts and subassemblies available from ResMed. 7 Calibration procedures – Lists procedures to follow after a fault has been isolated to a PCB or blower and the part has been replaced. Follow these procedures to calibrate the unit and to restore the owner's individual settings. 8 Troubleshooting guide – Gives you a way to quickly locate the problem and fix it if you know the symptoms of a faulty machine. 9 System specifications – Lists electrical and mechanical specifications of flow generator and air tubing. 10 Recommended maintenance schedule – Provides a brief description of the maintenance which the owner of the flow generator should carry out. If the owner is performing regular cleaning and maintenance, there is no need for regular servicing by a service technician. Some countries require all medical equipment to have a periodic service to confirm that the equipment is in good working order. Section 3 General inspection and servicing may be used in this situation. Appendix A: Service Request Form - Whenever you locate a fault in a flow generator, fill out this form and return it to ResMed for logging. Appendix B: Noise reduction upgrade - Lists procedures to follow to reduce noise in problem flow generators. Appendix C: Installing the service software - Lists procedures for installing the service software. Note:

4

Schematics of all PCBs in this flow generator are available to authorised service centres. To order, please contact your local ResMed office.

VPAP® III, VPAP III ST, VPAP III ST-A Service Manual

2

Introduction This manual is a guide to servicing and repairing the VPAP III, VPAP III ST and VPAP III ST-A flow generator and humidifier. It is written for ResMed distributors, and gives instructions for replacing subassemblies and for recalibration as appropriate. Work at the component level will normally be carried out by ResMed.

Intended users of this manual Before attempting any repair work, please ensure that you: • are familiar with the operating manual and the clinical manual for the flow generator • have suitable electrical and mechanical training to satisfy the requirements of the relevant regulatory authorities • use the correct antistatic procedures described in this manual Use only approved ResMed parts and never use parts that have failed, show excessive wear, have been contaminated, or are ineffective for their intended use. Note:

Schematics of all PCBs in this flow generator are available to authorised service centres. To order, please contact your local ResMed office.

Nasal CPAP Nasal Positive Airway Pressure systems are used to treat obstructive sleep apnea, a disorder that causes a physical obstruction in a person’s airway while sleeping. The principle of treatment is that filtered air is delivered by a flow generator through flexible tubing to a nasal mask worn by the patient while sleeping. The flow generator maintains a positive pressure in the patient’s airway which acts as a pneumatic splint, preventing the airway from collapsing during sleep.

Features of the VPAP III, VPAP III ST The VPAP III system provides continuous positive airway pressure (CPAP) and bi-level therapy to patients with obstructive sleep apnea (OSA). The device delivers a treatment pressure with a maximum range of 2 to 25 cm H2O depending on the unit’s configuration. The data storage and processing capabilities of the VPAP system facilitate patient management. The system provides summary data for a variety of time intervals, which can be viewed via the LCD menus. The patient’s usage hours, mask leak, tidal volume, respiratory rate, minute ventilation, apnoea + hypopnoea index (AHI), and apnoea index (AI) are displayed in the Results section of the Clinical menu.

Features of the VPAP III ST-A The VPAP III ST-A provides bi-level therapy. It combines the features of the VPAP III series along with adjustable trigger and cycle thresholds, and a range of clinician and patient alarms.The device delivers a treatment pressure with a maximum range of 2 to 30 cm H2O depending on the unit’s configuration.

HumidAire 2i™ The HumidAire 2i is designed to integrate with the VPAP III system to form a single heated humidification and VPAP unit.

ResLink The ResLink clinical therapy management module is designed to integrate with the VPAP III system. It provides greater insights into therapy and visible, objective evidence that the device is delivering effective ventilation during sleep. 2 Introduction

5

Software changes ResMed continually develops and improves its products. The VPAP III, VPAP III ST and VPAP III ST-A have undergone a number of software changes as outlined below:

VPAP III, VPAP III ST Software version

Significant features

SX365-0108

• Original issue

SX365-0109

• Maintenance update • Update to shipper states • First VPAP III ST release

SX365-0200

• Number of used hours displayed extended to 8760

VPAP III ST-A

6

Software version

Significant features

SX384-0106

• Original issue

SX384-0107

• Maintenance upgrade with language fixes.

SX384-0108

• Maintenance upgrade

SX384-0203

• Number of used hours displayed extended to 8760

SX384-0200 (Teijin only)

• Original issue

SX384-0202 (USA only)

• Original issue

VPAP® III, VPAP III ST, VPAP III ST-A Service Manual

3

General inspection and servicing Instructions for general inspection procedures Carry out the procedures on the following pages to confirm that the flow generator is in good electrical and mechanical condition. These tests will highlight any major mechanical or electrical problem with the unit. Enter the results in the electronic form provided in the service software.

Equipment required • ResMed Spirit 2.1 Service Software (30967) or available in service software kit 30966, which includes null modem cable, oxygen sideport connector, closed Bubble Cushion®, standard mask frame and security key. Note: Instructions for installing the Spirit 2.1 Service Software can be found in Appendix C: Installing the service software. • Calibrated flow meter with flow regulation valve Note: The flow meter must be capable of measuring air flows ranging from 0 to 150 L/min with an accuracy of 3% or better over this range • 2 metre air hose • Manometer (0-30 cm H2O range) • A computer running Windows NT 4.0, 2000 or XP. Note:

There is only partial support for the VPAP III ST-A on a computer running Windows NT 4.0. Some command settings will not be available.

• HumidAire 2i docking station

For VPAP III ST-A only • DC-24/30 converter (ResMed part# 22015) • DC power supply (12V battery or bench top power supply capable of supplying 3 amps or more)

3 General inspection and servicing

7

Software buttons Flow generator settings dialog

Perform the audible alarm test

Perform the pressure calibration test

Service record results form

Perform the flow calibration test

Record

Perform the blower test

Function keys VPAP III and VPAP III ST keypad and LCD

LCD Screen Right key

Left key

Keypad Up/down key Front key

VPAP III ST-A keypad and LCD LCD screen

Quickview

LEDs

Left key

Right key

Start/Stop

Alarm mute

Up/down key

8

VPAP® III, VPAP III ST, VPAP III ST-A Service Manual

1

Clean the flow generator Before servicing the unit it should be wiped down using a lint free cloth and a cleaning agent with a high alcohol content, for example, isopropyl alcohol.

Caution

!

When using a cleaning agent with a high alcohol content refer to the appropriate Material Safety Data Sheet to ensure safe handling of the cleaning agent. Remove any stains from the cases. When removing any stains from the flow generator or mask system use soap or detergent-based cleaning solutions. Remove excess and wipe dry after use. Do not use thinners, trichlorethylene, bleach or other solvents. Do not apply oil to any component of the flow generator.

2

Record clinical settings 1 Open AutoSet Spirit Service Software 2.1.

Main window in service software

2 Select Settings>Flow generator settings from the main window, or press the Open flow generator settings dialog button at the top of the main window. 3 The following screen will appear with the flow generator settings:

4 Select File>Save screen settings to file, or select the floppy disk icon and save the settings under the unit’s serial number.

Warning

!

If the clinical settings can not be recorded, press the Default button and save the file with the default settings for the faulty unit. Notify the patient that the unit has been reset to default settings. 3 General inspection and servicing

9

3

External examination 1 Visually examine the flow generator for external damage such as: • deformation or cracking of the upper or lower cases • damaged components such as the mains power inlet or mains power switch • damage to the front panel decal or bottom decal If either of the outside cases are fractured and require replacement, take particular care in inspecting all other components within the cases for damage. 2 Press the Service record results button. 3 Open the file saved earlier, containing the unit’s clinical settings. 4 Check the appropriate box for the external examination.

4

Caution

!

Internal examination (if necessary) The VPAP III uses an isolated power supply, however, it is recommended that isolation transformers are also used for added safety while working with the cases opened up and power switched on. Remove the front cover, interface assembly and the top case of the flow generator by following the instructions given in Section 5 Replacing major subassemblies. Inspect the flow generator for the following, recording any irregularities: • The blower assembly is seated correctly • The Power Supply PCB is seated correctly Inspect the unit for the following, recording any irregularities: • all mechanical components are seated correctly • all electrical components are mounted correctly and secured in position • there are no loose terminals, loose wires or incomplete insulation on electrical components or connections • there are no loose pieces of wire or other objects trapped in the PCB Use an antistatic cloth or brush to remove dust or dirt from components and from the insides of the flow generator case. Repair or replace any missing or damaged external components. Rectify any problems either identified by the user or noted during servicing. Should any major components such as the blower assembly or the Main PCB require replacement, the recalibration procedure as given in Section 7 Calibration procedures must be performed before the unit is returned to the patient. Reassemble the flow generator. Record the results by checking the appropriate box in the Record of Service window.

Caution

!

10

Printed circuit boards can be damaged by static electricity. Please read the instructions in Section 4 Static Precautions before attempting to replace any PCBs. Thread cutting screws are used to fasten the cases of the flow generator. When replacing a thread cutting screw, turn the screw anti-clockwise until it fits into the previously cut thread. Otherwise the original thread may be stripped out.

VPAP® III, VPAP III ST, VPAP III ST-A Service Manual

5

Replace the air filter 1 Remove the filter cartridge from the flow generator. 2 Replace the air filter, with the blue side of the filter material facing out from the unit. 3 Check the appropriate box in the Record of Service window.

Caution

! 6

Only use genuine ResMed spare parts, because the filter affects the flow characteristics of the flow generator, which in turn affects the pressure supplied to the patient.

Keypad test 1 Switch off the flow generator, then switch it back on. Wait for the Welcome message to appear and check that the LCD back light and LEDs beneath the keypad are illuminated. Note:

The LCD backlight and LEDs may not be clearly visible in bright light.

2 Press the Left key to enter the patient menu. Use the up/down button to cycle through the menu and the Left and Right keys to set and change options. Confirm that all button presses produce the appropriate response. 3 Press the start button and confirm that the flow generator starts. Press the button again and confirm that the flow generator stops. 4 Record the results by checking the appropriate box in the Record of Service window. 5 Press the Floppy disk button to save the results. If the flow generator fails this test, replace the keypad by following the procedures given in Section 5 Replacing major subassemblies. Once the keypad has been replaced, repeat the keypad test procedure. 7

Caution

!

Pressure calibration test Make sure the flow generator has been warmed up for at least 15 minutes before proceeding with the remaining tests 1 Close the Record of Service window. 2 Press the Record button and select the file which contains the flow generator settings. 3 Select Performance Tests>Pressure calibration test from the main window, or press the Perform the pressure calibration test button. 4 Set up the test equipment as instructed by the software. 5 Select Next and follow the steps as instructed. If the flow generator fails this test, follow the procedures outlined in Section 7 Calibration procedures to do a full recalibration of the flow generator.

3 General inspection and servicing

11

8

Flow calibration test 1 Select Performance Tests>Flow calibration test, or press the Perform the flow calibration test button at the top of the main window. 2 Set up the test equipment as instructed by the software. 3 Select Next and follow the steps as instructed. If the flow generator fails this test, follow the procedures outlined in Section 7 Calibration procedures to do a full recalibration of the flow generator.

9

Blower test The blower test is used to test the performance of the motor and to determine whether there are any impediments in the air path. 1 Select Performance Tests>Blower test, or press the Perform the blower test button at the top of the main window. 2 Set up the test equipment as instructed by the software. 3 Select Next and follow the steps as instructed. If the flow generator fails this test, check the flow generator airpath is clear and ensure the test set-up is correct. If the unit continues to fail, replace the blower then follow the procedures outlined in Section 7 Calibration procedures to do a full recalibration of the flow generator.

10 Audible alarm test 1 Select Performance Tests>Audible alarm test, or press the Perform the audible alarm test button at the top of the main window. 2 The following window will appear:

3 Follow the instructions on screen. Once complete press the Pass or Fail button to close the window. If the flow generator fails this test, the buzzer on the Main PCB will need to be replaced. After replacing the buzzer, repeat the Pressure calibration test, Flow calibration test and Audible alarm test from the general inspection procedures. 11 VPAP III ST-A alarm test (VPAP III ST-A only) 1 Hold down the alarm mute key for 3 seconds. 2 Once the key is released the alarm should sound and the LED should flash for 10 seconds.

12

VPAP® III, VPAP III ST, VPAP III ST-A Service Manual

12 DC power test (VPAP III ST-A only) 1 Turn off the flow generator at the mains. 2 Take the DC-24/30 converter and adjust the voltage to 24V. 3 Place the converter on a level surface with the ResMed logo facing upwards. 4 Plug the flat connector end of the DC-24/30 converter into the DC input socket. 5 Connect the DC-24/30 converter to a DC power source (12V battery or bench top power supply capable of supplying 3 amps or more) 6 Turn on the unit at the DC connector and confirm that the unit powers up. 7 Turn off the unit and reconnect it to mains power. 13 HumidAire 2i test The VPAP III, VPAP III ST and VPAP III ST-A is designed to integrate with the ResMed HumidAire 2i heated humidifier. The units automatically detect the HumidAire 2i docking station when it is connected to the flow generator.

Warning

!

The HumidAire 2i heating plate may reach temperatures in excess of 60°C. 1 Switch off the flow generator. 2 Remove the VPAP III front cover by referring to the instructions given in Section 5 Replacing major subassemblies 3 Plug the HumidAire 2i docking station without the water chamber into the front of the flow generator as shown in the picture below.

Note:

The docking station may not attach correctly to the flow generator if docking is attempted with the water chamber installed.

4 Switch the flow generator on and observe the LCD screen. After a welcome message is displayed, the LCD screen should display the warm-up feature prompt.

3 General inspection and servicing

13

Note:

The VPAP III ST-A will display the standard patient menu or advanced patient menu series after the welcome message. Press the right key until the warm-up feature prompt is displayed.

5 Turn the knob to 5. 6 Press the right key to start the HumidAire 2i warming up. Ensure the light on the humidifier turns on to indicate the unit is warming.

Light indicating humidifier warming

7 For VPAP III and VPAP III ST units press the right button again to stop the warm-up feature. 8 Switch off the flow generator and remove the HumidAire 2i docking station.

Warning

!

The HumidAire 2i heating plate will be extremely hot (in excess of 60°c). 9 Refit the front cover. 10 Switch on the flow generator and observe the LCD screen. Confirm that the warm-up feature prompt is not displayed in the LCD screen. If the flow generator fails this test, switch off and remove the power cord. Remove the top cover and blower assembly by referring to the instructions given in Section 5 Replacing major subassemblies. Check that all cables inside the flow generator are connected correctly.

14

VPAP® III, VPAP III ST, VPAP III ST-A Service Manual

14 Reload clinical settings 1 Select Settings>Flow generator settings from the main window. 2 Select File>Read settings from file, or select the folder icon. 3 Navigate to where the settings file was saved and open the file. 4 Once the settings are displayed on the screen, click the Set button to upload them to the flow generator. 5 Close the Flow generator settings window. 15 Complete the Service record results form 1 Press the Service record results form button and open the file with the unit’s settings. 2 Press the Service details tab. • Check the Reload clinical settings box at the base of the window. • Check the Clean flow generator box to indicate if the unit was cleaned according to the procedures outlined in step 1 Clean the flow generator. • Check the appropriate HumidAire 2i test box. • Check the appropriate DC power test box. • Check the appropriate VPAP III ST-A alarm test box.

“

“ “

“

“

16 Fill out product problem report 1 If any problems are found with the flow generator, fill out the Service request form in Appendix A of this manual, and send it to ResMed in Sydney for review and logging. (The address may be found on the first page of this manual.) 2 Check the appropriate Fill out product problem report box in the Service details window. 3 Save the file. If a hard copy of the form is needed, press the Print button at the top of the window. 4 Close the Record of Service window. 3 General inspection and servicing

15

4

Static Precautions

Warning

!

Prior to disassembly or assembly, make sure that the power is not connected to the flow generator. Integrated circuits (ICs) within the various PCBs can be badly damaged by electrostatic discharge or transient voltages. The following procedures are recommended to avoid component damage: 1 Work benches where handling and repairs are done must have surfaces of suitable conducting material connected via a 1 MΩ resistor to an electrical ground. 2 The area under and also in front of the work bench must be coated with a suitable conductive floor paint, or alternatively covered with a conductive floor mat. The conductive paint coating or floor mat must be connected to an electrical ground. 3 Soldering irons or solder baths must be at the same reference (ground) potential as the work bench. 4 A wrist strap must be worn by service personnel working at the bench. The wrist strap must have a conductive lead (1 MΩ) connected to the bench surface. Alternatively, a heel grounding strap to ground the operator to the floor may be used. (Such a wrist or heel strap should not create an electrical hazard for the wearer). 5 Handling of ICs should be kept to a minimum. If handling is required, avoid directly touching the leads. The recommended procedure is to first touch the container in which the ICs are stored, or the PCB in which they are mounted, before touching the ICs. Service personnel should take every precaution that the items will see the same reference potential when moved. 6 All ICs and PCB assemblies containing ICs should be stored in antistatic bags until use. 7 Service personnel should wear clothing which minimizes the build up of static charges. Cotton is preferable to wool or synthetic fibres. 8 Service personnel should avoid electrostatic build up through the movement of air over plastic material. 9 Plastic materials should wherever possible be kept away from the ICs as they develop and maintain high levels of static charge. 10 Low humidity increases potential static problems. Maintaining humidity levels above 60% is one of the most effective ways to guard against static handling problems.

16

VPAP® III, VPAP III ST, VPAP III ST-A Service Manual

5

Replacing major subassemblies This section contains brief instructions and points to be aware of as you replace major subassemblies and reassemble the flow generator.

Caution

!

When a Main PCB or motor is replaced, the flow generator must be recalibrated by following the procedures in Section 7 Calibration procedures.

Outer components of the flow generator Handle

Top case

Interface panel

Filter

Front muffler assembly

Bottom case

Water chamber

Docking station

VPAP III with HumidAire 2i attached

5 Replacing major subassemblies

17

Opening the flow generator Remove the front muffler assembly 1 Press the latch underneath the front muffler assembly.

2 While pressing on the latch, pull away the front muffler assembly from the unit.

18

VPAP® III, VPAP III ST, VPAP III ST-A Service Manual

Removing the interface assembly 3 Using a screwdriver, release the two front lock tabs while pulling the interface assembly upwards.

Front lock tabs

Use a screw driver to push against locking tabs

4 Lift up the module carefully, so as not to place any strain on the flexible cable or PCB underneath.

5 Replacing major subassemblies

19