Maquet Servo-i Service manual (Rev5)

SERVO-i Ventilator System

Service Manual

SERVO-i Ventilator System Important

Notes

1 - 2 Service Manual Revision 05

Important SERVO-i Ventilator System

Contents

1. Important ......................................................................

2. Introduction ..................................................................

3. Description of functions ..............................................

4. Disassembling and assembling ..................................

5. Service procedures ......................................................

1

2

3

4

5

6. Troubleshooting ...........................................................

7. Preventive maintenance ..............................................

8. Index .............................................................................

9. Service Manual revision history ..................................

10. Diagrams ......................................................................

6

7

8

9

10

Revision 05 Service Manual 1 - 3

SERVO-i Ventilator System Important

Important

1

General

• Service documentation for the SERVO-i
Ventilator System consists of:

– User's Manual. The User's Manual is an

indispensable complement to the Service
Manual for proper servicing.

– Service Manual

– Installation Instructions

– Spare Parts information

– Documentation for all optional equipment

included in the SERVO-i System is also
available.

• The SERVO-i Ventilator System is referred to as
the SERVO-i troughout this manual.

• There are two serial number labels on the unit:

– One label is attached to the Patient Unit close

to the supply gas inlets. The serial number
stated on this label is the ID number of the
Patient Unit. The serial number is also stored in
the SW memory as the 'System ID'.

– One label is attached to the rear side of the

User Interface close to the On/Off switch. The
serial number stated on this label is the ID
number of the User Interface.

• System version number can be found in the
Status window on the User Interface. Make sure
that the version of the User's Manual
corresponds to the System version.

Symbols used in this manual

• ESD sensitive components. When
handling ESD-sensitive devices,
established procedures must be
observed to prevent damage.

• Special waste. This product contains
electronic and electrical components.
Discard disposable, replaced and left­over parts in accordance with
appropriate industrial and
environmental standards.

• Recycling. Worn-out batteries must
be recycled or disposed of properly in
accordance with appropriate industrial
and environmental standards.

• With power supply connected to the
SERVO-i, there are energized electrical
components inside the unit. Exercise
extreme caution if power supply
connected and covers are removed.

• When performing service on SERVO-i
systems approved for use in MR
environment, only accessories and
spare parts allowed for use in MR
environment must be used in order to
maintain the systems MR environment
status.

• Technical training. Refers to the
Technical training supplied by
MAQUET.

Text inside a box is used to highlight important
information.

• In addition to the Important information given
here and in the related documents (e.g. in the
User's Manual), always pay attention to
applicable local and national regulations.

• Responsibility for the safe functioning of the
equipment reverts to the owner or user in all
cases in which service or repair has been done
by a non-professional or by persons who are not
employed by or authorized by MAQUET, and
when the equipment is used for other than its
intended purpose.

1 - 4 Service Manual Revision 05

• Service contract. Refers to the
Service contract supplied by
MAQUET.

Installation

• Only personnel trained and authorized
by MAQUET shall be permitted to
install the SERVO-i. The installation
and handing-over procedures are
described in the 'SERVO-i Ventilator
System – Installation Instructions'.

Functional check

• After any installation, maintenance or
service intervention in the SERVO-i,
perform a 'Pre-use check' according
to instructions in the 'SERVO-i
Ventilator System – User's Manual'.

Important SERVO-i Ventilator System

Important

Service

• The SERVO-i must be serviced at
regular intervals by personnel trained
and authorized by MAQUET.
Any maintenance or service must be
noted in a log book provided.

• It is recommended that maintenance
and service is done as a part of a
service contract with MAQUET.

• For functionality enhancement, the latest released
System SW version is always recommended.

• Preventive maintenance must be performed at
least once every year as long as the unit is not
used more than normal. Normal operation is
estimated to correspond to approx. 5.000 hours
of operation. Details are found in this Service
Manual, chapter 'Preventive maintenance'.

• The Battery modules shall be replaced after two
and a half years from their manufacturing date.

• The internal Lithium batteries (on PC 1771 and
PC 1772) shall be replaced every five years.

• Worn-out batteries must be recycled or
disposed of properly in accordance
with appropriate industrial and
environmental standards.

• This product contains electronic and
electrical components. Discard
disposable, replaced and left-over
parts in accordance with appropriate
industrial and environmental standards.

• When working with ESD sensitive
components, always use a grounded
wrist band and a grounded work
surface. Adequate service tools must
always be used.

SERVO-i in MR environment

• SERVO-i systems approved for use in a
Magnetic Resonance (MR) environment
are marked with MR Conditional
stickers.

• When performing service on SERVO-i systems
approved for use in MR environment, only
accessories and spare parts allowed for use in
MR environment must be used in order to
maintain the systems MR environment status.

• For further information regarding SERVO-i in MR
environment, refer to:

– SERVO-i MR Environment Declaration

– SERVO-i, MR Environment kit – Installation

Instructions

– Spare Parts information.

Hazard notices

• Before disassembling or assembling of the
SERVO-i, make sure that the:

– On/Off switch is set to Off.

– Mains power cable is disconnected.

– Gas supply is disconnected (wall and/or

cylinder).

– Battery modules are disconnected.

– Regular cleaning and extended cleaning of the

inspiratory channel are performed. Refer to
instructions in the User's Manual.

• With power supply connected to the
SERVO-i, there are energized electrical
components inside the unit.
All personnel must exercise extreme
caution if fault tracing or adjustments
are performed with power supply connected and
with user interface and patient unit covers
removed.

To the responsible service personnel

• The contents of this document are not binding.
If any significant difference is found between the
product and this document, please contact
MAQUET for further information.

• We reserve the right to modify products without
amending this document or advising the user.

• Only personnel trained and authorized by
MAQUET shall be permitted to perform
installation, service or maintenance of
the SERVO-i. Only MAQUET genuine
spare parts must be used. PC boards
(spare parts) must always be kept in a package
for sensitive electronic devices. MAQUET will not
otherwise assume responsibility for the materials
used, the work performed or any possible
consequences of same.

• The device complies to standards and
requirements as stated in the 'SERVO-i Ventilator
System – User's Manual'.

1

Revision 05 Service Manual 1 - 5

SERVO-i Ventilator System Important

Important

Construction materials

The construction materials used in SERVO-i in %
of the total weight.

Metal – total 77%

• Aluminium 69%

• Steel, zink, brass 8%

Polymeric material – total 9%

• PA (Polyamide)

• POM (Polyoxymethylene)

• SI (Silicone)

• TPE (Thermoplastic elastomer)

• PUR (Polyurethane)

• ABS (Acrylicnitrilebutadienstyrene)

• EPDM (Ethylenepropylenedienemonomer)

• PTFE (Polytetrafluoroethylene)

• FPM (Fluororubber)

• NBR (Nitrilerubber)

• PP (Polypropylene)

• PVC (Polyvinyl chloride)

• PS (Polystyrene)

1

Environmental declaration

Purpose

This environmental declaration is for a SERVO-i
basic unit including the carrier and two batteries.

Letters codes within brackets refers to the
Functional Block Diagram in chapter Diagrams.

Components with special environmental concern

Components listed below shall be disposed of in
accordance with appropriate industrial and
environmental standards.

Printed circuit boards

• PC 1770 Main back-plane

• PC 1771 Control, including Lithium battery (C)

• PC 1772 Monitoring, including Lithium battery (M)

• PC 1775 Plug-and-Play back-plane (P)

• PC 1777 Panel including Backlight Inverter (U)

• PC 1778 DC/DC & Standard connectors (P)

• PC 1780 Pneumatic back-plane (I)

• PC 1781 Pressure transducer, 2 pcs (T)

• PC 1784 Expiratory channel (F)

• PC 1785 Expiratory channel connector (E)

• PC 1789 Remote alarm connector (A)

Other electronics

• TFT assembly including backlight (U)

• Touch screen (glass) (U)

•O2 cell, containing caustic lime and lead (Pb) (I)

•O2 Sensor, containing PC boards (I)

• Gas module Air, containing multiple PC boards (I)

• Gas module O2, containing multiple PC boards (I)

• AC/DC Converter, containing PC boards (P)

• Expiratory cassette (E)

• Expiratory valve coil (E)

• Safety valve pull magnet (I)

• Battery modules Nickel-Metal Hydride

•CO2 Analyzer Module, containing PC boards

• Edi Module, containing PC boards

• Y Sensor Module, containing PC boards

1 - 6 Service Manual Revision 05

Electronics – total 14%

• Battery modules Nickel-Metal Hydride

• Printed circuit boards, cables etc.

Others – very small amounts

• Filter paper of fibre glass

Important SERVO-i Ventilator System

Important

Articles of consumption

1. Bacteria filter

2. Filters for the gas modules

3. Filter for the inspiration pressure transducer

4. Filter for the O2 cell (if applicable)

5. Nozzle units for the gas modules

6. Battery modules

7. Lithium batteries

8. Expiratory cassette

9. Expiratory cassette membrane

10. O2 cell (if applicable)

11. Backlight lamps.

Item 1: Consumption approximately 250 pcs/year.

Items 2 – 5: Changed approx. every 5.000 hours.

Items 6: Changed approx. every 12.500 hours.

Items 7: Changed approx. every 25.000 hours.

Items 8 – 11: Changed when needed.

Articles related to clinical applications, e.g. patient
tubings, Y Sensors and NAVA catheters, not
included in the list above.

Noise level

Less than 50 dBA.

Packing materials

The amounts of packing materials will vary
depending on customer adaptation.

Materials for packing:

• Loading pallet. Fulfils the USA requirements
7 CFR 319.40 May 25’th 1995.

• Corrugated cardboard

• Stretch film of Polyethylene, PE.

• Shock-absorbing material of expanded
polyethylene, EPE, or expanded polypropylene,
EPP.

• Clamps of Polyethylene, PE.

Product End-of-Life

For scrapping information, refer to the document
'SERVO-i Ventilator System – Product End-of-Life
Disassembly Instructions.

1

Power consumption

The power consumption depends on the operating
mode and whether the internal batteries are being
fast or trickle charged.

Mode Fast charging Trickle charging

In operation 70 W 38 W

Standby 65 W 33 W

Off 35 W 6 W

Revision 05 Service Manual 1 - 7

SERVO-i Ventilator System Important

Notes

1

1 - 8 Service Manual Revision 05

SERVO-i Ventilator System Introduction

Only personnel trained and authorized
by MAQUET shall be permitted to
perform installation, service or
maintenance of the SERVO-i.

Make sure to prepare the SERVO-i properly
before disassembling and assembling. Refer to
section 'Hazard notices' in chapter 'Important'.

Any service or maintenance must be noted in a
log book.

After any installation, maintenance or service
intervention in the SERVO-i, perform a 'Pre-use
check'. Refer to the 'SERVO-i Ventilator System –
User's Manual' for details.

This product contains electronic and
electrical components. Discard
disposable, replaced and left-over parts
in accordance with appropriate
industrial and environmental standards.

2. Introduction

Main units ......................................................... 2 - 2

User Interface ................................................ 2 - 4

Patient Unit .................................................... 2 - 6

SERVO-i software structure.............................. 2 - 9

General........................................................... 2 - 9

Breathing ....................................................... 2 - 9

Monitoring ...................................................... 2 - 9

Panel .............................................................. 2 - 10

System ID ...................................................... 2 - 10

Edi ................................................................. 2 - 10

2

Revision 05 Service Manual 2 - 1

Introduction SERVO-i Ventilator System

Main units

The SERVO-i is available in different main
configurations:

• Adult

User Interface

2

Patient Unit

SERVO-i
Mobile Cart

• Infant

• Universal Basic edition

• Universal Extended edition

These main configurations are as standard equipped
with a number of ventilation modes suitable for each
patient category. Further ventilation modes can be
installed via SW Upgrades.

The SERVO-i can be divided into the following main
units:

• User Interface. The User Interface contains all
controls used to set the ventilation and monitoring
parameters. Ventilation parameters as well as other
important information are shown on the User
Interface display.

• Patient Unit. The Patient Unit contains pneumatics
and electronics for gas supply to the patient.
Power supply and battery backup is also contained
in the Patient Unit.

The Control cable connects the User Interface and
the Patient Unit.

The SERVO-i shown in the illustration is mounted
onto the optional SERVO-i Mobile cart.

A number of optional equipment can be added to the
SERVO-i Ventilator System. For further information,
refer to the documents listed below.

Aeroneb Pro and Aeroneb Solo

• Aeroneb Pro – Instruction Manual

• Aeroneb Solo – Instruction Manual

• Aeroneb Pro / Aeroneb Solo – Installation Instructions

Alarm output connector

• SERVO-i – User's Manual

• Alarm output connector – Installation Instructions

• Alarm output connector – Reference Manual

Battery module

• SERVO-i – User's Manual

• Battery module – Installation Instructions

2 - 2 Service Manual Revision 05

SERVO-i Ventilator System Introduction

Compressor Mini

• SERVO-i – User's Manual

• Compressor Mini – Operating Manual

• Compressor Mini – Service Manual

• Compressor Mini – Installation Instructions

CO2 Analyzer Module

• SERVO-i – User's Manual

•CO2 Analyzer Module, SERVO-i – Installation
Instructions

Edi Module (NAVA)

• NAVA Ventilation – User's Manual

• Edi Module – Installation Instructions

Gas cylinder restrainer

• SERVO-i – User's Manual

• Gas cylinder restrainer – Installation Instructions

Gas trolley

• SERVO-i – User's Manual

• Gas trolley – Installation Instructions

Heliox

• SERVO-i – User's Manual

• Heliox Adapter kit – Installation Instructions

Holder

• SERVO-i – User's Manual

• SERVO-i Holder – Installation Instructions

Note: MR Environment considerations.

Humidifier and Humidifier Holders

• SERVO-i – User's Manual

• Humidifier – Operating Manual

• Humidifier Holder – Installation Instructions

Loudspeaker booster kit

• Loudspeaker booster kit – Installation Instructions

Mobile cart

• SERVO-i – User's Manual

• SERVO-i Mobile cart – Installation Instructions

Note: MR Environment considerations.

MR Environment kit

• MR Environment declaration

• MR Environment kit – Installation Instructions

Servo Ultra Nebulizer

• SERVO-i – User's Manual

• SERVO Ultra Nebulizer, SERVO-i – Installation
Instructions

Shelf base

• SERVO-i – User's Manual

• SERVO-i Shelf base – Installation Instructions

Note: MR Environment considerations.

Support Arm 176/177

• SERVO-i – User's Manual

• Support Arm 176/177 – Installation Instructions

User Interface panel cover

• SERVO-i – User's Manual

• User Interface panel cover – Installation
Instructions

Y Sensor Measuring

• SERVO-i – User's Manual

• Y Sensor Module – Installation Instructions

2

Interhospital transport kit

• Interhospital transport kit – Interhospital transport
declaration

• Interhospital transport kit – Installation Instructions

Isolation shield with drip guard

• Isolation shield with drip guard – Installation
Instructions

IV Pole

• SERVO-i – User's Manual

• IV Pole, SERVO-i – Installation Instructions

Revision 05 Service Manual 2 - 3

Introduction SERVO-i Ventilator System

2

SVX9011

User Interface

The User Interface can be mounted onto the Mobile
cart but can also easily be removed from the cart
and mounted on the bed post or table/shelf.

The User Interface can be rotated and tilted into a
suitable position. Locking levers, mounting devices
and some other items are shown in the illustration
above.

1. Display with touch screen.

2. Fixed keys for immediate access to special
windows.

3. Main rotary dial.

4. Special function keys.

5. Direct access knobs.

6. Mains indicator (green).

7. Standby indicator (yellow).

8. Start/Stop (Standby) ventilation key.

9. Luminescence detector, adjusts display
brightness automatically. On User Interface of
Type 1, the detector is placed in the upper left
corner. On User Interface of Type 2, the detector
is placed above the Fixed keys in the upper right
corner.

10. Loudspeaker grid.

11. Cable reel.

12. PC Card slot with slot cover.

13. Control cable between User Interface and
Patient Unit.

14. Service connector.

15. On/Off switch and switch cover, version
discontinued in production Q2 2007.

16. On/Off switch and switch cover, version
introduced in production Q2 2007.

17. Panel holder

18. Locking screw, alternative mounting

19. Locking arm, rotation

20. Locking arm, tilting.

21. Serial number label. The serial number stated on
this label is the ID number of the User Interface.
This serial number must always be refered to
when ordering service, spare parts, etc for the
User Interface.

For further information regarding operation of the
User Interface, refer to the User's Manual.

2 - 4 Service Manual Revision 05

SERVO-i Ventilator System Introduction

hg

d

s

f

2

SVX9013

a

SVX9012

jk

When the front panel section is removed from the
rear cover, the following parts are accessible:

1. Touch screen including frame.

2. TFT Display.

3. Backlight lamps.

4. PC board Backlight inverter.

5. PC 1777 Panel including PC Card slot.

6. Loudspeaker.

7. Main rotary dial (rotary encoder with switch).

8. Direct access controls (rotary encoder).

The illustration above shows User Interface of Type 2.

Revision 05 Service Manual 2 - 5

Introduction SERVO-i Ventilator System

2

SVX9014

Patient Unit

The Patient Unit can be rotated on and pulled out of
the SERVO-i Mobile cart. It can also be mounted
onto a SERVO-i Holder or a SERVO-i Shelf base.

Items accessible from the outside of the Patient Unit
are shown in the illustration above.

1. Handle.

2. Gas inlet for Air. The gas inlet for Air can also be
used for the optional Heliox adapter.

3. Gas inlet for O2.

4. Equipotentiality terminal.

5. Mains supply connector incl. fuses F11 and F12.

6. Internal fan with filter.

7. Connector for external +12V DC battery power
supply.

8. Fuse F1 for external +12V DC power supply.

9. Optional connector.

10. Control cable connector.

11. Serial port for data communication (RS- 232).

12. Expiratory outlet.

13. Inspiratory section cover.

14. Expiratory inlet.

15. Module unit with six slots for connecting optional
modules, i.e. Battery modules, CO2 Analyzer
Module, Edi Module and Y Sensor Module.

16. Connector for Servo Ultra Nebulizer, SERVO-i.

17. Inspiratory outlet.

18. Alarm output connector (optional).

19. Serial number label. The serial number stated on
this label is the ID number of the Patient Unit.
The serial number is also stored in the SW
memory as the 'System ID'. This serial number
must always be refered to when ordering service,
spare parts, software updates/upgrades, etc.

2 - 6 Service Manual Revision 05

SERVO-i Ventilator System Introduction

as d f l;

When the Patient Unit front cover is removed, the
following parts are accessible:

1. PC 1772 Monitoring.

2. PC 1771 Control.

3. PC 1784 Expiratory channel with the two
connected PC 1781 Inspiratory and Expiratory
Pressure Transducers.

4. Expiratory valve coil.

5. Module unit including PC 1775 Plug-and-play
back-plane.

6. AC/DC Converter.

7. Internal fan.

8. Mains supply inlet.

9. PC 1778 DC/DC & Standard connectors.

10. PC 1785 Expiratory channel connector.

11. PC 1789 Remote alarm connector (optional,
not shown in the illustration).

2

SVX9045

ghjkA

DS

SVX9084

12. The PC boards, as listed above are directly or
indirectly connected to the PC 1770 Main back­plane.

13. The gas modules, the O2 Sensor/cell and the
safety valve pull magnet are connected to the
PC 1780 Pneumatic back-plane.

Revision 05 Service Manual 2 - 7

Introduction SERVO-i Ventilator System

2

FG

SVX9124

21

20

:

:

JK HL

The upper part of the Patient Unit contains the
inspiratory section and the expiratory section.

The main parts of the inspiratory section are the:

14. Two gas modules, Air and O2, for regulation of
the inspiratory gas.

15. Connector muff.

16. Inspiratory pipe with housings for the O2 Sensor/
cell and for the safety valve.

17. O2 cell incl. bacteria filter.

18. O2 Sensor. Alternative to the O2 cell for oxygen
concentration measurement.

19. Safety valve.

20. Temperature sensor (inside the connector).

21. Inspiratory pressure transducer tube incl. bacteria
filter, to connect the inspiratory pressure
transducer.

SVX9122

22

:

;

The expiratory cassette (22) is a complete unit.
It contains the following parts:

• Expiratory inlet with moisture trap.

• PC 1786 Expiratory channel cassette.

• Ultrasonic flowmeter.

• Heating foil to keep a stable temperature in the

expiratory gas.

• Pressure transducer connection, incl. bacteria

filter, to connect the expiratory pressure
transducer.

• Expiratory valve incl. valve membrane.

• Expiratory one-way valve.

The expiratory valve coil, mounted under the
expiratory cassette compartment, controls the valve
membrane in the cassette.

PC 1786 Expiratory channel cassette inside the
expiratory cassette is electrically connected to
PC 1784 Expiratory channel via PC 1785 Expiratory
channel connector (10).

SVX9123 SVX9120

2 - 8 Service Manual Revision 05

SERVO-i Ventilator System Introduction

SERVO-i software structure

PC1777 PANEL

PANEL SW

General

The SERVO-i SW installed in the ventilator will
contain all available system functionality. The
software is separated into different subsystems and
stored on some of the PC boards. The separation of
the software is handled by the installation program.

The SERVO-i SW is divided into the following
software subsystems:

• Breathing

• Monitoring

• Panel

• System ID

• Edi

Breathing

The Breathing SW controls the delivery of gases to
the patient. This subsystem is responsible for the
breathing system, that is:

• Ventilation control and regulation

• Inspiratory channel

• Expiratory channel

• Nebulizer control (software option)

The Breathing SW is stored on PC 1771 Control and
PC 1784 Expiratory Channel. The software must be
re-installed if PC 1771 or PC 1784 is replaced. New
software can be installed via a SW Service Release.

The Breathing SW is executed by microprocessors
on PC 1771 and PC 1784.

2

Monitoring

PC1784

PC1771

PC1772

BREATHING

SW

MONITORING

SW

SYSTEM ID

PC1770

Edi

Edi SW

SVX9143

Revision 05 Service Manual 2 - 9

SW

The Monitoring SW controls all monitoring and alarm
functions in the system, including trends of
measured values. Events, such as alarms and
change of settings will also be logged.

The Monitoring SW is stored on PC 1772 Monitoring.
The software must be re-installed if PC 1772 is
replaced. SW related to Monitoring is also stored in
the O2 Sensor. New software can be installed via a
SW Service Release.

The Monitoring SW is executed by the
microprocessor on PC 1772.

Introduction SERVO-i Ventilator System

Panel

The Panel SW controls all user interaction, as well as
software updating to all subsystems via the PC Card
interface.

The Panel SW is stored on PC 1777 Panel. The
software must be re-installed if PC 1777 is replaced.
New software can be installed via a SW Service
Release.

2

The Panel SW is executed by the microprocessor on
PC 1777.

System ID

The System ID SW is a configuration file, stored on
PC 1770 Main back-plane, that is unique for each
ventilator. The System ID SW will enable the
functions selected for this ventilator.

To change the functions of the ventilator, a new
System ID SW can be installed via an Option
Upgrade.

When replacing PC 1770 Main back-plane, a spare
part that is factory programmed for the concerned
ventilator must be used.

Edi

The Edi SW processes and filters the signals from the
Edi Catheter, and transmits Edi and leads data to the
ventilator.

The Edi SW is stored on PC 1874 Edi Module. New
software can be installed via a SW Service Release.
If an Edi Module is part of the system, make sure that
this module is connected during software installation.

The Edi SW is executed by the microprocessor on
PC 1874.

2 - 10 Service Manual Revision 05

SERVO-i Ventilator System Description of functions

Only personnel trained and authorized
by MAQUET shall be permitted to
perform installation, service or
maintenance of the SERVO-i.

Make sure to prepare the SERVO-i properly
before disassembling and assembling. Refer to
section 'Hazard notices' in chapter 'Important'.

Any service or maintenance must be noted in a
log book.

After any installation, maintenance or service
intervention in the SERVO-i, perform a 'Pre-use
check'. Refer to the 'SERVO-i Ventilator System –
User's Manual' for details.

This product contains electronic and
electrical components. Discard
disposable, replaced and left-over parts
in accordance with appropriate
industrial and environmental standards.

3. Description of functions

About this chapter ............................................ 3 - 2

Memory types used in the SERVO-i ................. 3 - 2

User Interface ................................................... 3 - 2

User Interface controls .................................. 3 - 2

PC 1777 Panel ............................................... 3 - 2

Loudspeaker .................................................. 3 - 2

Backlight Inverter ........................................... 3 - 3

Touch screen including frame ....................... 3 - 3

TFT Display with Backlight ............................ 3 - 3

Patient unit ........................................................ 3 - 3

Inspiratory section ......................................... 3 - 3

Expiratory section .......................................... 3 - 6

PC 1770 Main back-plane ............................. 3 - 8

Pressure transducers..................................... 3 - 8

PC 1771 Control ............................................ 3 - 8

PC 1772 Monitoring ....................................... 3 - 9

PC 1784 Expiratory Channel ......................... 3 - 9

Power supply ................................................. 3 - 9

Module unit .................................................... 3 - 10

Internal fan ..................................................... 3 - 11

Optional PC board slots ................................ 3 - 11

Battery module .............................................. 3 - 11

Control cable .................................................... 3 - 11

Optional equipment .......................................... 3 - 12

Aeroneb Pro and Aeroneb Solo ..................... 3 - 12

Alarm output connector ................................. 3 - 12

Battery module .............................................. 3 - 12

Compressor Mini ........................................... 3 - 12

CO2 Analyzer module ..................................... 3 - 12

Edi Module (NAVA) ........................................ 3 - 13

Gas cylinder restrainer ................................... 3 - 13

Gas trolley ...................................................... 3 - 13

Heliox ............................................................. 3 - 13

Holder ............................................................ 3 - 13

Humidifier and Humidifier Holder .................. 3 - 14

Interhospital transport kit .............................. 3 - 14

Isolation shield with drip guard...................... 3 - 14

IV Pole ............................................................ 3 - 14

Loudspeaker booster kit ................................ 3 - 14

Mobile cart ..................................................... 3 - 14

MR Environment kit ....................................... 3 - 14

Servo Ultra Nebulizer ..................................... 3 - 14

Shelf base ...................................................... 3 - 15

Support Arm 176 and Support Arm 177........ 3 - 15

User Interface panel cover ............................ 3 - 15

Y Sensor Measuring ...................................... 3 - 15

3

Revision 05 Service Manual 3 - 1

Description of functions SERVO-i Ventilator System

About this chapter

This text refers to the Functional Main Blocks
diagram in chapter 'Diagrams'.

Memory types used in SERVO-i

There are four different types of memories used in
the SERVO-i:

• Flash memory. For System SW storage. Present on
PC 1771, PC 1772, PC 1777, PC 1784 and in the
O2 Sensor and the Edi Module. The System SW
can be re-installed/updated using a SW Service
Release.

• RAM. For temporary storage of software and data.

3

Present on PC 1771, PC 1772 and PC 1777 and in
the CO2 Module, Edi Module and Y Sensor Module.

• Non-volatile memory. RAM with battery backup.
For settings, trends and logs. Present on PC 1771
and PC 1772.

• EEPROM. For PC board information, configuration,
calibration data, etc. Present on almost all PC
boards and in the O2 cell, CO2 Module, Edi Module
and Y Sensor Module. In the O2 Sensor, an
EEPROM is emulated by the Flash memory.

User Interface

Functional Main Blocks diagram marking: 'U'.

There are two different versions of the User
Interface. In this manual, they are described as:

• Type 1 – Up to User Interface S/N 114000
(SERVO-i S/N 17000).

• Type 2 – User Interface S/N 114001
(SERVO-i S/N 17001) and higher.

There is no difference in the clinical operation
between the two versions, but the electronics inside
the User Interface differs. As a consequence, some
of the spare parts are not compatible between the
two versions. Further information can be found
below and also in the SERVO-i Spare Parts List.

User Interface controls

Setting of different parameter input values is made
with the help of the following different interface
devices:

• Main Rotary Dial (rotary encoder with switch).

• Direct Access Knob, 4 each (rotary encoders).

• Membrane buttons. Integrated parts of the Touch
screen assembly.

• Touch screen.

PC 1777 Panel

Some features included on PC 1777 Panel are:

• SIMM (Single In-line Memory Module) mounted on
its connector P77. Memory type: SDRAM

• PC Card Slot intended for connection/insert of a
PC Card. PC Cards are used to:

– Download software into the different flash

memories situated on PC-boards marked µP and
into the EEPROM on PC 1770 Main back-plane.

– Transfer patient and system data for further

transfer to a computer.

– Service purpose.

• Microprocessor µP on this board includes control
of the functions of the User Interface.

• ID-PROM: The ID information can be read by the
SERVO-i.

• On/Off switch: Switch to Power up or Power down
the SERVO-i. Refer to section 'Power supply'.
A new design of the On/Off switch and the switch
cover was introduced Q2 2007. Refer to chapter
'Disassembling and assembling' for further
information.

• Service connector (P86): Ethernet port for MCare
Remote Services.

• Microphone used to monitor of sounds from the
Loudspeaker.

There are two different versions of PC 1777, Type 1
and Type 2. The PC 1777 spare part is not
compatible between the two versions.

For PC 1777 of Type 2, System SW version V2.00.04
or higher is required.

Note: The System SW must be re-installed if
PC 1777 is replaced.

Note: MR Environment considerations.

Loudspeaker

For generation of sound, e.g. alarm. Connected to
P72 on PC 1777 Panel.

The loudspeaker generates different tones with
individual sound volumes. At startup and during Pre­use check the function of the loudspeaker is
monitored by the microphone on PC 1777. During
operation it is continuously monitored through
current sensing.

With the optional accessory 'Loudspeaker booster
kit', the alarm sound is amplified. Refer to section
Optional equipment.

3 - 2 Service Manual Revision 05

SERVO-i Ventilator System Description of functions

Backlight Inverter

PC board with driving stage for backlight (lamps)
mounted behind the TFT Display. The supply voltage
delivered by the Backlight Inverter is 660 V.

The Backlight Inverter is connected to P73 on
PC 1777 Panel.

There are two different versions of the Backlight
Inverter, Type 1 and Type 2. The Backlight Inverter
spare part is not compatible between the two
versions.

Touch screen including frame

The Touch screen implies the touch function of the
front panel screen and is interactive with information
displayed on the TFT Display. The front panel frame
with the touch screen, membrane buttons and DIM
sensor forms the assembly Touch screen including
frame and must be handled as one complete part.
The DIM sensor measures the ambient light and the
screen brightness is automatically adjusted.

There are two different versions of the Touch screen
including frame, Type 1 and Type 2. The Touch
screen including frame spare part is not compatible
between the two versions.

Patient unit

Inspiratory section

Functional Main Blocks diagram marking: 'I'

The main block Inspiratory Section conveys the
breathing gas from its gas inlets for Air and O
supply to the patient breathing system. It comprises
the following main functions:

• Gas Modules – Air and O2. The Air Gas Module can
also be used for Heliox (HeO2), refer to section
'Heliox' below in this chapter.

• Connector Muff.

• Inspiratory Pipe.

•O2 Sensor/cell.

• Temperature Sensor.

• Inspiratory Pressure Tube.

• Safety Valve incl. pull magnet.

• Inspiratory Outlet.

• PC 1780 Pneumatic back-plane.

Gas modules – Air and O

The Air and O2 Gas Modules regulates the inspiratory
gas flow and gas mixture.

2

2

3

TFT Display with Backlight

The TFT Display is a Thin Film Transistor Screen for
color display of picture- and alphanumeric data.

There are two different versions of the TFT Display:

• Type 1 with Backlight consisting of two separate
fluorescent lamps mounted behind the TFT Screen.

• Type 2 with Backlight consists of one fluorescent
lamp mounted behind the TFT Screen.

The TFT Display spare part is not compatible
between the two versions.

The Backlight lamps are driven from the Backlight
Inverter. Estimated lifetime (with acceptable
brightness level) for the lamps is 30.000 hours.
Using the Field Service System (FSS), a time meter
for the lamps can be shown. The time meter must be
reset after replacement of the lamps.

Note: MR Environment considerations.

SVX9003

1.Filter

2.Inspiratory valve temperature sensor

3.Supply pressure transducer

4.Flow transducer (Delta pressure transducer and net)

5.Nozzle unit with valve diaphragm

6.Inspiratory solenoid

The Gas Modules are factory calibrated. Each Gas
Module must not be disassembled further than
described in chapter 'Preventive maintenance'.

Revision 05 Service Manual 3 - 3

Description of functions SERVO-i Ventilator System

Gas inlet
Gas supply is connected to the ventilators gas inlet

nipples. The design of the gas inlet nipples vary
according to the standard chosen.

Gas is to be connected from hospital central gas
supply or from gas cylinders. The Air supply may be
connected from a compressor for medical air.

Refer to 'Technical data' in the User's Manual for gas
quality specifications.

For Heliox information refer to section 'Heliox' below
in this chapter.

Filter

3

The Filter protects the ventilator from particles in the
gas delivered to the Gas Modules. The filter must be
replaced during the 'Preventive maintenance'.

The filter housing and the filter cover are provided
with matching guide pins. These guide pins prevent
mounting of the filter cover (with gas inlet nipple) on
the wrong module.

A non-return valve for the gas inlet is located in the
filter cover. This valve will suppress short pressure
drops in the gas supply.

The non-return valve is also designed to slowly
evacuate compressed gas from the module, if the
gas supply to the module is disconnected.

Nozzle unit
The plastic Nozzle Unit contains a valve diaphragm.

The valve diaphragm, controlled by the Inspiratory
Solenoid, regulates the gas flow through the Gas
Module.

The complete plastic nozzle unit must be replaced
during the 'Preventive maintenance'.
After replacement, allow the diaphragm to settle
during approx. 10 minutes before gas pressure is
connected to the Gas Module.

Inspiratory solenoid
The gas flow through the Gas Module is regulated by

the Inspiratory Solenoid via the Nozzle Unit.

The current supplied to the solenoid is regulated so
that the gas module will deliver a gas flow according
to the settings on the User Interface.

Gas module key
The Gas Modules are provided with a mechanical

key to prevent that the module is mounted in the
wrong slot.

The key consists of a plastic guide mounted
underneath the module and a corresponding guide
mounted in the patient unit.

Inspiratory valve temperature sensor
The temperature of the supplied gas is measured by

the Inspiratory Valve Temperature Sensor. This
sensor is situated in the gas flow.

The output signal from this sensor is used to
compensate for the gas density variations due to
temperature.

Supply pressure transducer
The pressure of the supplied gas is measured by the

Supply Pressure Transducer.

The output signal from this transducer is amplified. It
is then used to calculate the absolute pressure of the
gas to compensate for gas density variations due to
pressure.

Flow transducer
The gas flows through a net (resistance) which

causes a pressure drop. The pressure is measured
on both sides of this net and the differential pressure
value is then amplified.

ID PROM

Each Gas Module is provided with an ID-PROM. The
ID information can be read by the SERVO-i System.

Connector muff

The Connector Muff connects the Gas Module
outlets to the Inspiratory Pipe inlet.

Inspiratory pipe

The Inspiratory Pipe leads the gas from the
Connector Muff to the Inspiratory Outlet.

The Inspiratory Pipe comprises:

• Housing for the O2 Sensor as well as housing and
locking lever for the O2 cell with its bacteria filter.

• Housing for the Safety Valve.

• Connection for measurement of inspiratory
pressure.

The pipe is provided with internal flanges with the
purpose to improve mixing of O2 and Air.

The O2 Sensor requires a changed design of the
Inspiratory pipe. The O2 Sensor and the Inspiratory

3 - 4 Service Manual Revision 05

SERVO-i Ventilator System Description of functions

pipe are equipped with a mechanical key to prevent
that the O2 Sensor is mounted on wrong type of
Inspiratory pipe. The O
versions of the Inspiratory pipe.

O

cell

2

cell can be used on both

2

The O2 cell is mounted in a housing on the
Inspiratory pipe and is protected by a bacteria filter.

Maintenance including exchange of bacteria filter
according to the User´s manual. The bacteria filter
must also be replaced during the 'Preventive
maintenance'.

The O2 cell gives an output voltage proportional to
the partial pressure of oxygen inside the Inspiratory
pipe. At constant ambient pressure this output is
proportional to the O2 concentration in percent.

In each O2 cell, the output signal will stay at a fairly
constant level usually within 10–17 mV in normal air
and at standard barometric pressure during the life
time of the cell.

The life time of the cell is affected by the O
concentration. With a concentration (at the cell) in %

2

and expected cell life time in hours the following
applies at 25oC (77oF):

O2 Conc. x Expected cell life = 500 000% hours.

The O2 cell is automatically calibrated each time a
Pre-use check is performed (if O2 is connected to the
ventilator).

If the ventilator has continually been in use for a long
time, the measured O2 concentration may drop due
to normal degradation of the O2 cell. This will activate
a nuisance alarm. For further information, refer to the
User's Manual.

Note: Pre-use check is recommended to use to
calibrate the O2 cell.

An ID PROM is integrated into each O2 cell. Its ID
information and remaining lifetime can be read by
the SERVO-i.

O2 Sensor

The O2 Sensor is mounted in a housing on the
Inspiratory pipe as an alternative to the O2 cell.

3

SVX9110

The O2 Sensor is a measuring device for the inspired
oxygen concentration, using ultrasound technique
with two ultrasonic transducers/receivers.

The sound velocity in oxygen is lower than in air.
By measuring the sound velocity in a binary gas mix,
where the two gases are known (air and oxygen),
the ratio between the gases can be calculated,
i.e. O2 concentration.

The technique for the O2 Sensor is similar to the one
in the expiratory cassette, with one transducer
transmitting an ultrasonic pulse through the gas and
the other one receiving the pulse. The measured
time difference between the transmission and the
reception of the pulse is used for calculation of the
sound velocity, which is then used for calculation of
the O2 concentration.

A temperature sensor inside the O2 Sensor measures
the gas temperature and this measurement is used
when calculating the O2 concentration.

The O2 Sensor cannot be used with the Heliox
option.

Each O2 Sensor is provided with an ID-PROM. The
ID information can be read by the SERVO-i System.

Temperature sensor

A Temperature Sensor is integrated into the
connector on top of the O2 Sensor/cell.
This Temperature Sensor measures the temperature
inside the Inspiratory Section.

The output signal, corresponding to the temperature
in the Inspiratory Section, is used for regulation of
the Internal Fan. The electronics for this regulation is
located on PC 1775 Plug-and-play back-plane.

Revision 05 Service Manual 3 - 5

Description of functions SERVO-i Ventilator System

Inspiratory pressure tube

The Inspiratory Pressure Tube connects the Inspira­tory Pipe with the Inspiratory Pressure Transducer.
A bacteria filter protects the pressure transducer on
PC 1781 Pressure Transducer from contamination.

Maintenance including exchange of bacteria filter
according to User´s manual. The bacteria filter must
also be replaced during the 'Preventive maintenance'.

Safety valve

The movable axis of the Safety Valve Pull Magnet
controls the opening and closing of the safety valve
membrane in the Inspiratory Pipe. The pull magnet is
electrically activated (closed) from the main block

3

Expiratory Channel.

When the Safety Valve is not activated, the weight of
the pull magnet axis, in combination with the design
of the valve membrane, pushes the pull magnet axis
downwards. This actuates the Safety Valve to be
opened and the inspiratory gas is let out from the
Inspiratory Pipe via the Safety Outlet thus enabling a
decrease in the inspiratory pressure. The Safety
Outlet is covered by a plastic grid.

This is normal safety (pop-off) function.

The opening conditions for the safety valve are:

• The ventilator is switched Off or to Standby.

• The pressure inside the inspiratory pipe is
5 cm H2O above the preset Upper Pressure
Alarm limit. This condition is controlled by the
Monitoring subsystem.

• The pressure inside the inspiratory pipe is
7 cm H2O above the preset Upper Pressure
Alarm limit. This condition is controlled by the
Breathing subsystem.

• The pressure inside the inspiratory pipe is above
117 ±7 cm H2O. This is an extra safety function
and this situation will normally not occur.

• The safety valve will also be opened by some other
alarms, e. g. the Out of gas-alarm.

During startup, the pull magnet is electrically
activated so that the pull magnet axis is pushed up
(with a clicking sound). This is the normal operational
position of the pull magnet; the Safety Valve is
normally kept closed.

The safety valve opening pressure is calibrated to
117 ±3 cm H2O during each Pre-use check.

Inspiratory outlet

22 mm / 15 mm tube connector for the inspiratory
tube of the patient breathing system.

PC 1780 Pneumatic back-plane

Interconnecting board including connectors for
cables to the Gas Modules as well as to the Safety
Valve and to the O2 Sensor/cell and the Temperature
Sensor.

Expiratory section

Functional Main Blocks diagram marking: 'E'.

The main block Expiratory Section conveys the
breathing gas from the patient breathing system to
the Expiratory Outlet. It comprises:

• Measurement of expiratory flow

• Connection for measurement of expiratory
pressure.

• Controlling element for the regulation of expiratory
pressure.

Expiratory cassette

The expiratory gas conveying parts and PC 1786
Expiratory Channel Cassette are integrated into one
part – the Expiratory Cassette – which can be easily
removed for cleaning or exchange. See SERVO-i
Ventilator System – User’s Manual.

The expiratory cassette can be interchanged between
different SERVO-i systems. A Pre-use check is
always required after exchanging the expiratory
cassette.

A re-designed version of the Expiratory cassette was
introduced during Q1 2005 starting with cassette S/N

35000. The new cassette has a larger pressure

transducer channel and this will significantly reduce
the drying time needed before use.

PC 1786

Ultrasonic

transducer

Inlet

SVX9017

Heating

foil

Expiratory

channel cassette

Bacteria

filter

Ultrasonic

transducer

Expiratory pressure

tube connector

Outlet

3 - 6 Service Manual Revision 05

SERVO-i Ventilator System Description of functions

Expiratory inlet
22 mm / 10 mm tube connector for the expiratory

tube of the patient breathing system. The inlet is
designed to make condensed water drip out and
allow use of a water trap for such water to be
collected. Expiratory inlet bacteria filter can be
connected to protect the cassette from
contamination.

Heating foil
An electrical Heating Foil applied on the outside of

the expiratory pipe where the Ultrasonic Flowmeter
is situated. The purpose of the Heating Foil to reduce
condensation and maintain a stable temperature in
the expiratory gas.

Ultrasonic flowmeter
The Ultrasonic Flowmeter is a measuring device for

the expiratory gas flow, using ultrasound technique
with two ultrasonic transducers/receivers.
The measuring process is controlled from the main
block PC 1784 Expiratory Channel.

SVX9018X

The time difference between the downstream and
the upstream time measurements provides flow
information.

A temperature sensor inside the cassette measures
the expiratory gas temperature. This temperature
measurement is also used when calculating the
expiratory flow.

The sound velocity in Heliox is higher than in air.
By measuring the sound velocity in the gas mix,
it will be detected if Heliox is used.

Bacteria filter and expiratory pressure tube
Via a Bacteria Filter inside the cassette, the

Expiratory Pressure Tube connects the cassette to
the Expiratory Pressure Transducer. The filter and
the connector are integrated parts of the cassette.
The filter protects the transducer on PC 1781
Pressure Transducer from contamination.

Expiratory valve
The Expiratory Valve consists of a membrane in the

cassette that is operated by the axis of the
Expiratory Valve Coil. The valve is fully open as long
as no power is supplied to the coil.

Operating capacity for the membrane is estimated to

10.000.000 breathing cycles. When this limit is
passed or if the membrane for some reason has
become defective, it must be replaced. Refer to
instructions in chapter 'Disassembling and
assembling'.

Remaining operating capacity (in %) for the
membrane can be shown in the Status window.
Select Status / Exp. cassette to check 'Remaining
membrane capacity'. The operating capacity meter
must be reset after replacement of the membrane.

3

The left hand side transducer is sending out
ultrasonic sound that is reflected against the inner
wall of the expiratory channel. The ultrasonic sound
is received by the right hand side transducer now
acting as a receiver. The time from sending to
receiving ultrasonic sound in downstream expiratory
gas flow is measured.

Then the right hand side transducer (earlier receiving)
is sending out ultrasonic sound upstream the
expiratory gas flow. The ultrasonic sound is received
by the left hand side transducer now acting as a
receiver. The time from sending to recieving
ultrasonic sound in upstream expiratory gas flow is
measured.

Revision 05 Service Manual 3 - 7

Expiratory valve coil
The movable axis of the Expiratory Valve Coil

controls the opening of the Expiratory Valve by
pushing the valve membrane into desired position.
The power supply to the coil is regulated so that the
remaining pressure in the patient system, towards
the end of the expiration time, is kept on the PEEP
level according to front panel setting.

Expiratory outlet with expiratory one-way valve
The gas from the patient system leaves the ventilator

via this Expiratory Outlet. Backflow via the cassette
is prevented by the Expiratory One-Way Valve. Its
rubber membrane and valve seat are integrated
parts of the Expiratory Outlet.

Description of functions SERVO-i Ventilator System

PC 1786 Expiratory channel cassette
The PC 1786 Expiratory Channel Cassette is a

connection board, integrated into the Expiratory
Cassette, for the Ultrasonic Flowmeter and for the
Heating Foil. It connects to PC 1785 mounted in the
expiratory cassette compartment.

Includes an ID PROM. The ID information can be
read by the SERVO-i System.

PC 1785 Expiratory channel connector

The PC 1785 Expiratory Channel Connector is a
connector board including signal filters that is
mounted in the expiratory cassette compartment.
It connects to PC 1786 mounted in the Expiratory

3

Cassette when the cassette is docked to the
expiratory cassette compartment.

PC 1770 Main back-plane

Interconnection board for the PC boards in the lower
part of the patient unit.

The ventilators System ID (Serial No.), configuration,
operating time, etc, is stored in an EEPROM on PC

1770. Thus, when replacing PC 1770, a spare part
that is factory programmed for the concerned
ventilator must be used.

As the preventive maintenance time stamp will be
reset when replacing PC 1770, a new time stamp
must be set via the Biomed menu. In order to make
this new time stamp correct, the preventive
maintenance must be performed. Refer to chapter
'Preventive maintenance'.

Pressure transducers

Functional Main Blocks diagram marking: 'T'.

PC 1781 Inspiratory pressure transducer

The pressure, conveyed via the pressure tube
connected to this block, is led to and measured by
its differential pressure transducer. With differential
reference to the ambient pressure, the output signal
is proportional to the measured pressure thus giving
a linear measurement in the range -40 cm H2O to
+160 cm H2O.

Technical limitation: Pressure exceeding ±400 cm
H2O must be avoided.

Includes an ID PROM. The ID information can be
read by the SERVO-i System.

PC 1781 Expiratory pressure transducer

Function identical to PC 1781 Inspiratory Pressure
Transducer.

PC 1771 Control

Functional Main Blocks diagram marking: 'C'.

The main block Control comprises microprocessor
control of Breathing pattern for all different
ventilation modes.

Electronics including microprocessor (µP) control to
achieve:

1. Regulation of Inspiratory flow which is used

during inspiration time in Volume Control (VC)
mode.

2. Regulation of Inspiratory pressure which can be

used during inspiration time in any mode.

3. Regulation of a constant Inspiratory flow which is

used during expiration time in all modes.

4. Respiratory timing pattern including frequency as

well as distribution of the duration for Inspiration
time, Pause time and Expiration time according
to front panel settings.

5. Regulation of Inspiratory flow during inspiration

time. The desired total Inspiratory flow value
according to front panel settings is used to
generate the flow reference signals Insp Flow Ref
1 and Insp Flow Ref 2. The level relation between
these two flow reference signals depends on the
desired O2 concentration according to front
panel setting. Insp Flow Ref 1 and Insp Flow Ref
2 are used for the control of its respective Gas
Module (Air and O2).

Regulation of a constant Inspiratory flow during
expiration time: The desired constant Inspiratory flow
value is the default Bias flow value (see User’s
Manual).

This desired constant Inspiratory flow value is used
to generate the flow reference signals Insp Flow Ref 1
and Insp Flow Ref 2 with the same relation and same
handling as described above under 'Regulation of
Inspiratory flow…' except this occurs during
expiration time.

The electronics controlling the optional Servo Ultra
Nebulizer is located on PC 1771 Control.

Includes an ID PROM. The ID information can be
read by the Servo-i System.

Note: The System SW must be re-installed if PC
1771 is replaced.

A lithium battery on PC 1771 power supplies the
internal memory on the PC board. If the battery on
PC 1771 is disconnected or if the battery voltage is
too low, user default configurations made via the
Field Service System (FSS) and Pre-use check
results including transducer calibrations will be
erased. The lithium batteries must be replaced after
5 years.

Note: MR Environment considerations.

3 - 8 Service Manual Revision 05

SERVO-i Ventilator System Description of functions

PC 1772 Monitoring

Functional Main Blocks diagram marking: 'M'.

The main block Monitoring comprises microprocessor
(µP) calculation of parameters and monitoring of
alarm limits with control of alarms (as well as back­up alarm). The main block Monitoring co-operates
with the Loudspeaker in the User Interface.

The PC 1772 Monitoring handles all supervision and
alarms in the system. It activates pressure reducing
mechanisms, including activation of the safety valve,
in case of excessive breathing system pressure.

All alarms are conveyed and displayed on the front
panel and the alarm sound is also generated. In case
of malfunction in the loudspeaker located on PC
1777 Panel, a backup sound generating device
(buzzer) on PC 1772 will be activated automatically.
This buzzer is monitored by a microphone at startup
and during the Pre-use check.

The following voltages are supervised:

• +24 V

• +12 V

• -12 V

• +5 V

• +3.3 V

The buzzer on PC 1772 Monitoring generates the
alarm signal in case of +5 V or +3.3 V power failure.
The buzzer and +5 V / +3.3 V failure logic is powered
by backup capacitors in case of power failure.

The alarm signal used by the optional 'Alarm output
connection' is generated on PC 1772.

PC 1772 also contains a barometric transducer and
the measured barometric pressure is supplied to the
other sub-units in the system.

Trending of measured parameters are performed by
Monitoring.

A thermistor on PC 1772 monitors the temperature
inside the Patient Unit. An alarm is activated if the
temperature is 77 ±5 °C (170 ±9 °F) or higher.

Includes an ID PROM. The ID information can be
read by the SERVO-i System.

Note: The System SW must be re-installed if PC
1772 is replaced.

A lithium battery on PC 1772 power supplies the
internal memory on the PC board. If the battery on
PC 1772 is disconnected or if the battery voltage is
too low, all logs and Pre-use check results including
transducer calibrations will be erased. The lithium
batteries must be replaced after 5 years.

Note: MR Environment considerations.

PC 1784 Expiratory channel

Functional Main Blocks diagram marking: 'F'.

The main block Expiratory channel comprises
microprocessor control to achieve measurement of
expiratory flow. The output signal Exp. Flow is used
in the main block Control.

Electronics including microprocessor (µP) for
handling of:

• All electronic connections to and from the
Expiratory Section functions.

• Measurement of airway pressures in both
Inspiratory Section and Expiratory Section.

• Control of the Safety Valve functions in the
Inspiratory Section.

A thermistor on PC 1784 monitors the temperature
inside the Patient Unit. An alarm is activated if the
temperature is 77 ±5 °C (170 ±9 °F) or higher.

Includes an ID PROM. The ID information can be
read by the SERVO-i System.

Note: The System SW must be re-installed if PC
1784 is replaced.

Note: MR Environment considerations.

Power supply

Functional Main Blocks diagram marking: 'P'.

The main block Power Supply comprises conversion
of mains power to internal power supply as well as
the Module unit-connections for optional Battery
modules and/or other optional modules.

The power modes in the SERVO-i System are:

• At Power up, i. e. when the On/Off switch is turned
On, all internal voltages will be enabled.

• At Power down, the Power supply system will
deactivate the hardware signal Power_Good.H,
and at the same time keep the internal voltages +5
V and +3.3 V for at least 1 ms, in order to let the
different subsystems save their current settings in
non-volatile memory. Power down can be caused
by:

– Turning the On/Off switch Off.

– Mains failure resulting in a switch to battery, but

the backup battery voltage is too low for proper
operation of the system or no backup battery
connected.

– The system is powered from a battery, but the

battery voltage becomes too low for proper
operation of the system.

In this Off mode, only charging of Battery modules
is enabled (if the system is connected to mains).
All other circuitry is un-powered.

3

Revision 05 Service Manual 3 - 9

Description of functions SERVO-i Ventilator System

• In Standby all circuitry is powered from the Power
supply, but no breathing will be active. The
operator can set all parameters, including
breathing mode, during Standby.

If the internal DC supply voltage +12 V_Unreg drops
below 10 V, due to power supply failure, the power
supply source will automatically switch. The
following power supply source priority is used:

1. Mains power

2. External +12 V DC supply (if connected)

3. Backup Battery modules.

Power supply selection is managed by:

• PC 1778 – Between Mains power and External

3

+12 V DC power supply.

• PC 1775 – Between Mains power/External
+12 V DC and Battery module power supply.

Mains inlet

Inlet for mains power supply including grounding
connection.

The SERVO-i System will automatically adjust to the
connected mains power if the mains power is within
specified range. No voltage or frequence setting is
required.

The mains inlet is equipped with two mains power
fuses, F11 and F12, rated 2.5 A.

Note: MR Environment considerations (two ferrite
blocks mounted on the mains power cable).

AC/DC Converter

Converts the connected AC Power to the internal DC
supply voltage +12 V_Unreg.

PC 1778 DC/DC & Standard connectors

Converts the internal DC supply voltage +12 V_Unreg
into the following internal DC supply voltages:

• +24 V

• +12 V

• -12 V

• +5 V

• +3.3 V

PC 1778 also controls switching between Mains
power and External 12 V DC power supply.

All standard connectors are located on this board.
The connectors are the following:

• N26 – External +12 V DC supply input. The
connector is equipped with a fuse F1, rated 10 A.
There are no alarms indicating power supply failure
related to the External +12 V DC supply. Thus,
when the External +12 V DC supply is used,
backup Battery modules must be installed to
ensure proper operation.

• N27 – Optional equipment.

• N28 – Control cable.

• N29 – RS232.

Pin configuration and signal names can be found in
chapter 'Diagrams'.

Includes an ID PROM. The ID information can be
read by the SERVO-i System.

PC 1775 Plug-and-play back-plane

Connects the Optional Modules that are inserted in
the Module Unit.

PC 1775 also controls:

• Charging / discharging of the Battery modules.

• Switching between Mains power/External 12 V DC
and Battery module power supply.

• Internal fan using input signals from the
Temperatur sensor in the O2 Sensor/cell connector.

Includes an ID PROM. The ID information can be
read by the SERVO-i System.

Module unit

Connection slots for 6 optional modules, i.e. Battery
modules, CO2 Analyzer Module, Edi Module and
Y Sensor Module.

3 - 10 Service Manual Revision 05

SERVO-i Ventilator System Description of functions

Internal fan

The Internal Fan forces cooling air through the
Patient Unit. The cooling air flow inside the Patient
Unit is indicated in the 'Functional Main Block
Diagram'. The cooling air outlets are located in the
expiratory section.

The Internal Fan is controlled by the Temperature
Sensor in the O2 Sensor/cell connector via
electronics on PC 1775 Plug-and-play back-plane.

The fan will start with half effect at approx. 33 °C
(91 °F) and with full effect at approx. 43 °C (109 °F).
When the temperature drops below approx. 37 °C
(99 °F), the fan turns to half effect and when the
temperature drops below approx. 27 °C (81 °F),
the fan stops.

The air inlet is protected by a filter that must be
cleaned or replaced during the 'Preventive
maintenance'.

Optional PC board slots

Functional Main Blocks diagram marking: 'X'.

For optional equipment, the SERVO-i is equipped
with two extra PC-board slots.

The optional Alarm output connector (see below) is
mounted in one of the extra PC-board slots.

Battery module

The Battery module is a 12 V / 3.5 Ah Nickel-Metal
Hydride rechargeable 'smart battery'. Up to six
backup Battery modules can be connected to the
Module unit. To guarantee safe battery backup,
always use at least two batteries.

To calculate its own status, the battery uses an
internal highly accurate voltmeter, amperemeter and
time clock to measure actual charge in and out of
the battery. In addition, there are algorithms to
compensate for the effects of discharge rate,
discharge temperature, self-discharge and charging
efficiency, etc.

Even with this technology, the only time at which the
battery charge status is absolutely reliable is when it
is either completely full or completely empty. What’s
more, if the battery only sees partial charges and
discharges during its application, then it may not get
the benefit of a 'full' or 'empty' reference point for
some time, and must rely more and more on its
calculated figure.

The life span for the Battery module is calculated to
two and a half year from manufacturing date. Normal
time for logistics and storage are included in this
calculation. The calculation corresponds thus to an
estimated operational time of two years.
Manufacturing date (year-week) is printed on the
battery label.

System SW version V2.01.00 (or higher) includes an
improved monitoring of the battery status. This
System SW will, among others, monitor:

• Expiry date.

• If the operational capacity is too poor for continued
usage.

In both cases, battery replacement information will
be shown on the User Interface.

Select 'Status / Batteries' on the User Interface to
check battery status. For further information, refer to
chapter 'Service procedures', section 'Battery
modules'.

With the charge status indicator on the User
Interface, the four green LEDs on the Battery module
are no longer required and will be removed from the
Battery modules.

Recharge time for a discharged battery is approx.
3 hours/battery. If a battery is fully discharged, e.g.
due to long storage time, it may require up to 12
hours charging time.

Each battery includes an ID PROM. The ID
information can be read by the SERVO-i System.

Control cable

This Control Cable connects the Patient Unit and the
User Interface. The cable can be partly winded up
under a rubber cover on the rear of the User
Interface.

Note: The Control cable must only be connected or
disconnected when the ventilator is switched Off.

Note: MR Environment considerations (two ferrite
blocks mounted on the Control cable).

3

Revision 05 Service Manual 3 - 11

Description of functions SERVO-i Ventilator System

Optional equipment

Aeroneb Pro and Aeroneb Solo

The Aeroneb® Nebulizer Systems, Aeroneb Pro and
Aeroneb Solo, are devices intended to aerosolize
physician-prescribed medications, for inhalation, that
are approved for use with a general purpose
nebulizer.

The Aeroneb Pro / Aeroneb Solo are designed to
operate in-line with standard ventilator circuits and
mechanical ventilators in acute and sub acute care
environments. It operates without changing patient
ventilator parameters.

• Aeroneb Pro: Nebulizer system using the Aeroneb

3

Pro control module and the reusable nebulizer unit.

• Aeroneb Solo: Nebulizer system using the Aeroneb
Pro-X control module and the single use nebulizer
unit Aeroneb Solo.

The Aeroneb Pro / Aeroneb Solo are delivered with
an allround mounting bracket and adapter. For
SERVO-i, an additional holder (accessory) is
available.

The Aeroneb Pro / Aeroneb Solo are an in sourced
finished product manufactured by Aerogen Limited.
For further information, refer to manufacturer's
documentation.

Alarm output connector

Functional Main Blocks diagram marking: 'A'.

PC 1789 Remote alarm connector containing the
optional function Alarm output connector is mounted
in the extra PC-board slot located below PC 1778
DC/DC & Standard connectors.

The Alarm output connector enables connection of
an external alarm signal system to the SERVO-i. High
and medium priority alarms are transferred, and the
alarm output signal is active as long as the audio
alarm is active on the ventilator.

The Alarm output connector has two contact
functions: NO (Normally Open) and NC (Normally
Closed). In an alarm situation the open contact will
close and the closed one will open. The contacts are
independent of polarity and can be used both with
AC and DC systems.

Preferably the NC contact should be used, as this
will detect any interruption in the alarm system or
unintentional disconnection of the cable between the
system and the ventilator. Furthermore, if both the
NO- and the NC-contacts are utilized, an even higher
safety level for unforeseen failures can be achieved.
Note that, in both cases, even an intentional
disconnection of the ventilator will trigger the
external alarm.

Pin configuration and signal names in P67 – Alarm
output connector can be found in chapter
'Diagrams'.

The Alarm output- function must be enabled in the
configuration software.

For further information, refer to the 'Alarm output
connector – Reference Manual'

Battery module

The Module unit allows up to six Battery modules.
To guarantee safe battery backup, always use at
least two batteries.

For further information, refer to section 'Battery
modules' above in this chapter.

Compressor Mini

The Compressor Mini is designed to supply
medicalgrade compressed air. The compressor has
a capacity of approx. 30 l/min at a pressure of 350 ­450 kPa (50 - 64 psi).

The Compressor Mini can be placed on the ventilator
cart to form a compact unit which is easy to move. It
can also be used as a stand-alone unit.

The Compressor Mini is well insulated against noise
and therefore does not cause disturbance when
used during operations.

The Compressor Mini is equipped with a standby
function. In the standby mode, the compressor will
start to deliver compressed air if the hospital central
gas supply fails.

For further information, refer to separate Compressor
Mini documentation.

CO2 Analyzer Module

The CO2 Analyzer Module is an optional accessory
that is connected to the Module unit.

The CO2 Analyzer option allows for continuous
monitoring shown in a waveform (capnogram) and as
numericals on the screen.

The CO2 Analyzer Module is, via a cable, connected
to a Capnostat sensor mounted on an airway
adapter at the Y-piece. The sensor uses a solid state
and IR based optical system with no moveable parts.
It measures the difference between a reference light
beam and one filtered for CO2 wavelength.

The CO2 Analyzer- function must be enabled in the
configuration software.

For electrical safety test of the module, refer to
standard procedures regulated by IEC/EN 60601-1
Class 1, Type BF or corresponding national standard.

3 - 12 Service Manual Revision 05

SERVO-i Ventilator System Description of functions

Edi Module (NAVA)

The Edi Module is an optional accessory used during
NAVA ventilation. The Edi Module requires one free
slot in the Module unit.

To enable NAVA, the following parts are required:

• Edi Module including Edi Cable with connectors
and Edi Test Plug. The test plug is used to verify
proper operation of the Edi Cable and Edi Module
before use.

• NAVA software. The NAVA software is individually
created for each specific ventilator and can only be
installed on this ventilator. The NAVA-function
must be enabled in the configuration software.

• Single-use Edi Catheter. The catheter is a feeding
tube with measuring electrodes. Available in
different sizes.

NAVA is based on measuring of the electrical activity
of the diaphragm (Edi) and then use this information
to control the ventilation. The information can also
be used for monitoring purposes.

The Edi Catheter is placed into the esophagus to the
gastric ventricle. The catheter receives the signals
from the diaphragm excitation. The Edi Module filters
the signals and passes them to SERVO-i which uses
the signals for monitoring and regulation. It also
displays the Edi signal as a waveform on the User
Interface.

The Edi Module is available in a 50 Hz and a 60 Hz
version (to be used in 50 Hz alt. 60 Hz environment).
A built-in filter removes interference from
surrounding equipment.

If an Edi Module is part of the system, make sure
that this module is connected during software
installation. Software stored in the module will be
checked/updated during the software installation.

If the Edi Module is exposed to rough handling, e.g.
dropped on the floor, an Electrical safety test of the
module must be performed. Refer to standard
procedures regulated by IEC/EN 60601-1, Class 1,
Type CF or corresponding national standards.

Gas cylinder restrainer

The Gas cylinder restrainer is mounted on the rear
side of the optional Mobile cart. It is intended for two
gas cylinders, max. volume 5 litres each.

Gas trolley

The Gas trolley is attached on the rear side of the
optional Mobile cart. It is intended for two gas
cylinders, max. weight 10 kg each.

Heliox

To enable the Heliox option, the following parts are
required:

• Heliox Adapter kit. There are four different Heliox
Adapter kits available; DISS, NIST/NIST, AGA/NIST
and FRENCH/NIST. The Heliox adapter is
connected to the Air inlet. A factory preset
pressure regulator on the adapter assures that
correct Heliox gas pressure (280 kPa) is supplied
to the gas module.

• Heliox software. The Heliox software is individually
created for each specific ventilator and can only be
installed on this ventilator. The Heliox-function
must be enabled in the configuration software.

Prerequisites for the Heliox option are:

•O2 cell must be used. O2 Sensor cannot be used
with the Heliox option.

• Heliox gas pressure supplied to the Heliox adapter
must be within the range 340–650 kPa (49–94 psi).

• PC 1784 Expiratory Channel must be of Revision
16 (or later).

• PC 1785 Expiratory Channel Connector must be of
Revision 03 (or later).

The type of gas used (Heliox or Air) will be detected
in the Expiratory cassette during the Pre-use check.
The gas type will also be automatically detected if
switched during operation. Gas type can also be
changed manually on the User Interface by pressing
Menu > Compensate > Gas type.

Note that:

• Time of automatic gas identification may be
prolonged when there are low tidal/minute volumes
and high O2 concentrations.

• Automatic gas identification is disabled for set O
concentrations higher than 75%.

When switching from Heliox to Air, this prolonged or
disabled gas identification may cause activation of
the Heliox gas supply alarm. As the system still is set
for Heliox, but supplied with Air where higher
pressure is alllowed, the alarm may be activated.

The Heliox option cannot be used with Y Sensor
Measuring.

2

Holder

The Holder is a mounting device for the Patient Unit.
It allows positioning of the Patient Unit on a bed,
stretcher or standard rail.

3

Revision 05 Service Manual 3 - 13

Description of functions SERVO-i Ventilator System

Humidifier and Humidifier Holder

Recommended active (heated) humidifiers are Fisher
& Paykel MR 730 and MR 850. For further
information, refer to manufacturer's documentation.

The Humidifier holder allows for left or right
positioning of the heated humidifier.

Interhospital transport kit

The Interhospital transport kit must be installed to
reinforce ventilators used during interhospital
transport:

The Interhospital transport kit contains:

3

 Battery module locking device.
 Gas module stabilizing bracket.
 Cable clamp for user interface control cable.
For further information regarding the Interhospital

Transport Option, refer to the 'Interhospital Transport
Declaration' included in the kit.

Isolation shield with drip guard

The optional Isolation shield with drip guard is
connected to the Expiratory cassette outlet.
The accessory will not affect the expiratory
resistance of the system.

The main purpose of this accessory is to protect the
expiratory outlet pipe from direct cooling draught
favoring condensation.

The drip guard will also collect water that may be
condensed during ventilation in connection with use
of dual-heated patient tube during active
humidification. The water collector has a maximum
volume of 100 ml.

IV Pole

The IV Pole is mounted on the rear rails or side rails
of the optional Mobile cart. It includes four hooks
with max. load 1.5 kg each. Max. load total 6 kg.

Loudspeaker booster kit

By installing the accessory Loudspeaker booster kit,
the alarm sound is amplified in a mechanical way.
The sound level will be increased significantly. This
increased sound level will raise the complete alarm
sound setting range (10%100%), i.e. also the lower
sound level range will be increased.

The Loudspeaker booster consists of a rubber collar
that is mounted onto the loudspeaker to direct the
sound towards the loudspeaker grid.

All parts required for the installation are included in
the Loudspeaker booster kit.

Mobile cart

The Mobile Cart is designed for carrying the User
Interface, the Patient Unit and all required optional
equipment.

The Patient Unit is positioned on a console so that it
can easily be moved from the Mobile Cart or rotated
(to switch sides for the patient breathing system).

The Mobile Cart has side rails for accessories such
as a humidifier and slots in the column for the
Support Arm, IV Pole, etc.

Two of the wheels can be locked.

MR Environment kit

To enable use of the SERVO-i in an MR (Magnetic
Resonance) environment, the MR Environment kit
must be installed in the concerned unit. The main
parts of the kit are:

 EMC shield for the TFT Display
 EMC absorber kit. Self-adhesive absorbers for

sensitive PC board components.
 Ferrite blocks for cables.
 MR stickers.
The complete procedure to classify a SERVO-i as

MR Conditional is described in the MR Environment
Declaration.

Servo Ultra Nebulizer

The Servo Ultra Nebulizer is intended for
administering nebulizing drugs to patients requiring
mechanical ventilation or positive pressure breathing
assistance via an endotracheal tube or face mask/
prongs.

The nebulizer operates continuously regardless of
ventilation mode setting. No extra gas volume is
added to the inspiratory minute volume and thus
neither the ventilator settings nor the readings are
affected.

The nebulizer module becomes disabled whenever
the ventilator is running on battery power to reduce
the power consumption.

The Servo Ultra Nebulizer- function must be enabled
in the configuration software.

3 - 14 Service Manual Revision 05

SERVO-i Ventilator System Description of functions

Shelf base

The Shelf base is a mounting device for the Patient
Unit. It allows positioning of the Patient Unit on a
shelf.

Support Arm 176 and Support Arm 177

Support Arm 176 and Support Arm 177 are two
almost identical accessories. They are however
equipped with different types of mounting device:

• Support Arm 176 is equipped with a clamp
intended for standard rails.

• Support Arm 177 is equipped with a mounting
device intended for the rear rails or side rails of the
optional Mobile cart.

User Interface panel cover

The User Interface panel cover protects the screen
from inadvertent activation of settings and
mechanical damage during transport.

While attached, the user can still access the vital
settings. When raised, the user can access the
screen.

3

Y Sensor Measuring

The Y Sensor Measuring is an optional accessory
with the main parts:

• The Y Sensor Module that is connected to the
Module unit.

• The Y Sensor software option.

• The single-use Y Sensor including airway adapter
and tubing with connector. The Y Sensor is
available in adult and infant versions.

The Y Sensor Measuring is based on the fixed
orifice, differential pressure sensor technology, and
allows the pressure and flow to be measured as
close as possible to the patient's airway. The Y
Sensor Measuring can be used in all ventilation
modes.

The Y Sensor Measuring-function must be enabled
in the configuration software.

Y Sensor Measuring cannot be used with the Heliox
option.

Revision 05 Service Manual 3 - 15

Description of functions SERVO-i Ventilator System

Notes

3

3 - 16 Service Manual Revision 05

SERVO-i Ventilator System Disassembling and assembling

Only personnel trained and authorized
by MAQUET shall be permitted to
perform installation, service or
maintenance of the SERVO-i.

Make sure to prepare the SERVO-i properly
before disassembling and assembling. Refer to
section 'Hazard notices' in chapter 'Important'.

Any service or maintenance must be noted in a
log book.

After any installation, maintenance or service
intervention in the SERVO-i, perform a 'Pre-use
check'. Refer to the 'SERVO-i Ventilator System –
User's Manual' for details.

This product contains electronic and
electrical components. Discard
disposable, replaced and left-over parts
in accordance with appropriate
industrial and environmental standards.

4.Disassembling and assembling

General.............................................................. 4 - 2

Preparations...................................................... 4 - 2

Handling PC boards ......................................... 4 - 2

Replacing PC boards ........................................ 4 - 2

Assembling guidelines ...................................... 4 - 2

Tightening torque ........................................... 4 - 2

Threadlocking adhesives ............................... 4 - 2

User Interface ................................................... 4 - 3

PC 1777 Panel ............................................... 4 - 4

Backlight inverter ........................................... 4 - 6

TFT Display .................................................... 4 - 7

Backlight lamps ............................................. 4 - 9

Touch screen including frame ....................... 4 - 10

Membrane foil ................................................ 4 - 12

Patient Unit ....................................................... 4 - 14

4

Front cover ..................................................... 4 - 14

PC 1771, PC 1772 and PC 1784 ................... 4 - 15

AC/DC Converter ........................................... 4 - 15

Module unit including PC 1775 ..................... 4 - 16

PC 1778 DC/DC & Standard connectors ...... 4 - 18

Internal fan ..................................................... 4 - 18

PC 1789 Remote alarm connector ................ 4 - 19

PC 1770 Main back-plane ............................. 4 - 19

Inspiratory channel ........................................ 4 - 20

Safety valve membrane ................................. 4 - 20

PC 1780 Pneumatic back-plane .................... 4 - 20

Gas modules .................................................. 4 - 21

PC 1785 Expiratory channel connector......... 4 - 23

Expiratory valve coil ....................................... 4 - 23

Expiratory cassette membrane ...................... 4 - 24

Expiratory one-way valve .............................. 4 - 25

Fixed Battery module..................................... 4 - 26

Control cable .................................................... 4 - 26

Revision 05 Service Manual 4 - 1

Disassembling and assembling SERVO-i Ventilator System

General

Disassembling of the SERVO-i is described in this
chapter. If not stated otherwise, the assembling
procedure is the reverse of the described
disassembling procedure.

The illustrations in the SERVO-i Spare Parts Lists are
very useful as a guide when disassembling and
assembling the SERVO-i .

Preparations

Before disassembling or assembling the SERVO-i:

• Set the On / Off switch on the User Interface
to Off.

• Disconnect the mains power cable.

• Disconnect the gas supplies (wall and/or

4

cylinder).

• Disconnect Battery modules.

• Make sure that all gas conveying parts are
cleaned according to instructions in the
'SERVO-i Ventilator System – User's Manual'.

After any service intervention in the SERVO-i,
perform a 'Pre-use check' according to
instructions in the 'SERVO-i Ventilator System –
User's Manual'.

Replacing PC boards

The SERVO-i software is distributed on different
subsystems, located on the following PC boards:

• PC 1771 Control

• PC 1772 Monitoring

• PC 1784 Expiratory Channel

• PC 1777 Panel.

When delivered as spare parts, these PC boards are
equipped with a 'System SW version' that may differ
from the version on the unit to be repaired.
To keep the 'System SW version' used prior to the
PC board replacement, the applicable 'System SW
version' must be available on a PC Card for re­installation purposes.

For functionality enhancement, the latest released
'System SW version' is always recommended.

Before installing a new 'System SW version' on a unit,
ensure that the software is fully compatible with all
HW-, SW- and mechanical components in the unit.
If any compatibility conflicts are apparent this will be
noted on the 'MCC SW download' website.

Note: MR Environment considerations.
EMC absorbers are mounted on some
components on the PC boards listed
above. Refer to the 'MR Environment kit –
Installation Instructions'.

Handling PC boards

The PC boards contain components that
are highly sensitive to static electricity.

Those who come into contact with circuit
boards containing sensitive components
must take certain precautions to avoid damaging the
components (ESD protection).

When working with ESD sensitive components,
always use a grounded wrist band and grounded
work surface. Adequate service tools must also be
used.

PC boards (spare parts) must always be kept in
protective packaging for sensitive electronic device.

PC boards must not be inserted or removed while
the mains power or battery power is applied to the
PC boards.

Remove and insert the PC boards very carefully to
avoid damage to the connectors.

Assembling guidelines

The SERVO-i system specifications allow unit
operation also during patient transportation. Almost
all parts of the User Interface and the Patient Unit
assembled with screws and nuts are therefore
tightened with a specified torque and secured with
threadlocking adhesives.

In order to maintain these specifications over time,
it must be ensured that after any service intervention
removed parts are re-assembled and secured
according to instructions. Make sure to follow the
guidelines stated below.

Tightening torque

• Thread size M3: 0.95 ±0.05 Nm

• Thread size M4–M6: 3.1 ±0.1 Nm.

Threadlocking adhesives

• Electrolube Bloc'Lube BLV15ML® on threads in
contact with PC boards.

• Loctite 243® on all other threads.

Note: Threadlocking adhesive is not required on
Heli-Coil® screw thread inserts as these screw
thread-inserts have a self-locking function.

4 - 2 Service Manual Revision 05

SERVO-i Ventilator System Disassembling and assembling

User Interface

With power supply connected to the
SERVO-i, there are energized electrical
components inside the unit, e. g. the
backlight lamps that are supplied with
660 V by the Backlight Inverter.
All personnel must exercise extreme caution if
fault tracing or adjustments are performed with
power supply connected and with the user
interface rear cover removed.

ssa

SVX9020

ss

g

There are two different versions of the User
Interface. In this manual, they are described as:

• Type 1 – Up to User Interface S/N 114000
(SERVO-i S/N 17000).

• Type 2 – User Interface S/N 114001
(SERVO-i S/N 17001) and higher.

The electronics inside the User Interface differs and
as a consequence, some of the spare parts are not
compatible between the two versions. Further
information can be found below and also in the
SERVO-i Spare Parts List.

The User Interface in the adjacent illustration is
equipped with the On/Off switch cover introduced
Q2 2007. Refer to section 'PC 1777 Panel' for further
information.

To separate the front panel section from the rear
cover:

• Disconnect the control cable (1).

• Remove the screws (2). Threadlocking adhesive is
not used on these screws.

• Lift off the rear cover from the front panel section.

All parts inside the front panel section are now
accessible.

When removing the rear cover:

• The PC Card eject button can catch on the PC
Card slot during disassembling. Carefully release
the button from the rear cover before removing the
cover.

When mounting the rear cover on units with the new
version of the On/Off switch and switch cover:

• The switch must be set to 'On' before mounting
the rear cover. If set to 'Off', the switch lever will
not enter the hole in the switch cover.

4

The main parts of the User Interface are:

• Rear cover (3).

• PC 1777 Panel (4).

• Backlight Inverter (5).

• Support plate (6).

• TFT Display (7) including Backlight lamps.

• Touch screen including frame (8).

On MR Environment approved units, an
EMC shield is mounted between the

SVX9021

hfjkd

Revision 05 Service Manual 4 - 3

Touch screen and the TFT display.
Refer to the 'MR Environment kit –
Installation Instructions'.

Disassembling and assembling SERVO-i Ventilator System

SVX9022

4

Type 1 = PC 1777A – D

ss

ssa

ss

PC 1777 Panel

PC 1777A – D = Type 1

PC 1777F or higher = Type 2

To remove PC 1777 Panel (1):

• Carefully disconnect all cable connectors from
PC 1777.

• Remove the screws (2) holding PC 1777.

• Lift off PC 1777.

Note: When replacing PC 1777 Panel, it can be
necessary to re-install the System SW. For further
information, refer to section 'Replacing PC boards' in
this chapter. For PC 1777 of Type 2, System SW
version V2.00.04 or higher is required.

On MR Environment approved units,
EMC absorbers are mounted on some
components on PC 1777.

A new design of the On/Off switch was introduced
Q2 2007. This switch also requires a new version of

SVX9089

ssa

Type 2 = PC 1777F or higher

On/Off switch and switch cover - Old design

SVX9144

4 - 4 Service Manual Revision 05

the switch cover. Refer to illustrations below.

With this new design, the switch cover will be kept
open when the switch is Off and will be closed only
when the switch is On.

PC 1777 Panel, when delivered as spare part, will be
equipped with the new design of the On/Off switch.
The spare part will thus also include a new switch
cover to be mounted on the User Interface.

On/Off switch and switch cover - New design

SERVO-i Ventilator System Disassembling and assembling

Replacement of PC 1777 Type 1

PC 1777 Type 1 is discontinued and no longer
supplied as spare part. To replace such PC 1777,
the 'Replacement kit for PC 1777A–D' must be used.

Note: The Disassembling/Assembling instructions
and the illustration below is valid only for the
'Replacement kit for PC 1777A–D'.

The kit contains all parts required for the
replacement:

• PC 1777 of Type 2 (6)

• PC 1777–TFT Display cable of Type 2 (10)

• Support plate (5)

• Cushion for the EMC filter (9)

• Retainer (12)

• Screw, M3x8 mm (24 each)

• Screw, M3x6 mm (4 each).

dfg jS

hk ; lA

Disassembling

Installation of the replacement kit must be performed
in a clean and dustfree environment as the TFT
Display is sensitive to contaminations.

• Separate the front panel section from the rear
cover.

• Remove the loudspeaker (3) from the support plate.

• Remove PC board Backlight Inverter (4) from the
support plate (5).

• Remove the support plate including PC 1777 Panel
(6) and TFT Display (7) from the front panel section.

• Remove the TFT Display from the support plate.

• Discard the old PC 1777, the support plate and the
PC 1777–TFT Display cable of Type 1.

Assembling

• Check type and version of the TFT Display (7).

• Adapt the setting of the DIP switch (8) on the new
PC 1777 to the TFT Display. Refer to section 'TFT
Display' below.

• Mount the TFT Display (7) onto the new support
plate (5) using the new M3x6 mm screws.

• Attach the cushion (9) onto the EMC filter (11) as
shown in the illustration.

• Connect the cable (10) to the TFT Display.
Organize the cable, place the EMC filter in the
support plate recess and secure with the retainer
(12) as shown in section 'TFT Display' below.

• Mount the remaining parts onto the new support
plate. Use the new M3x8 mm screws.

– PC 1777 (6)

– PC board Backlight Inverter (4)

– Loudspeaker (3).

• Restore the complete assembly into the front panel
section.

• Connect all remaining cable connectors.

• Restore the User Interface.

4

Revision 05 Service Manual 4 - 5

Disassembling and assembling SERVO-i Ventilator System

Backlight Inverter

Type 1

To remove the PC board Backlight Inverter (1):

• Carefully disconnect the cable connector (2).

d

f

a

s

f

d

• Carefully disconnect the backlight lamp cable
connectors (3).

• Remove the screws (4) holding PC board Backlight
Inverter.

• Lift off PC board Backlight Inverter.

4

f

k

j

l

g

k

l

h

SVX9023

Type 2

To remove the PC board Backlight Inverter (5):

• Carefully disconnect the cable connector (6).

• Carefully disconnect the backlight lamp cable
connector (7).

• Loosen the screws (8).

• Remove the screws (9) holding PC board Backlight
Inverter.

• Lift off PC board Backlight Inverter.

Note: When assembling, make sure that the plastic
washers on screws (8) are fitted between the PC
board and the screwhead.

SVX9091

4 - 6 Service Manual Revision 05

SERVO-i Ventilator System Disassembling and assembling

TFT Display

Note: Disassembling of the TFT Display must be

performed in a clean and dustfree environment, as
the TFT Display is sensitive to contaminants.

Type 1

The TFT Display is mounted under the support
plate (1). To remove the TFT Display:

• Carefully disconnect all cables from PC 1777.
The Backlight Inverter cable and the Loudspeaker
cable can remain connected.

• Carefully disconnect the Backlight lamp cables
from PC board Backlight Inverter.

• Remove the screws (2) holding the support plate.

• Lift off the support plate-assembly, including TFT
Display and PC boards.

SVX9024

s

ass s

ss

4

ff

SVX9092

f

d

ff

g

f

Type 2

The TFT Display is mounted under the support
plate (3). To remove the TFT Display:

• Carefully disconnect all cables from PC 1777.
The Backlight Inverter cable and the Loudspeaker
cable can remain connected.

• Carefully disconnect the Backlight lamp cable from
PC board Backlight Inverter.

• Remove the screws (4) holding the support plate.

• Lift off the support plate-assembly, including TFT
Display and PC boards.

DIP switch on PC 1777 Type 2

Faulty DIP switch (5) setting will result in a reversed
display image.

Settings for TFT Display:

• SHARP LQ12S41 • SHARP LQ121S1DG11

• NEC NL8060BC31-27

Revision 05 Service Manual 4 - 7

Disassembling and assembling SERVO-i Ventilator System

• Remove the screws (6) holding the TFT Display to
the support plate.

SVX9025

4

SVX9026

k

h

Type 1

• Carefully release the Type 1-cable (7) from
PC 1777 as shown in the illustration.

j

Type 2

On units produced prior to Q2 2007, the Type 2­cable is secured with a self-adhesive cushion
mounted on the cable connector at the TFT Display.
There is also a similar cushion on the cables EMC­filter.

• To disconnect; carefully release the Type 2-cable
(8) from PC 1777 as shown in the illustration.

SVX9095

A new locking device for the Type 2-cable was
introduced Q2 2007. This device replaces the
cushion mounted on the cable connector at the TFT
Display. The cushion on the EMC-filter remains.

• Slide the locking device (9) into position until it
snaps in place. Note that there is no cushion on
the cable (10).

SVX9145

• The adjacent illustration also shows PC 1777
mounted onto the support plate and the Type 2-

l;l

cable connected to PC 1777. The locking device (9)
is visible between the support plate and PC 1777.

4 - 8 Service Manual Revision 05

SERVO-i Ventilator System Disassembling and assembling

Units with 'Replacement kit for PC 1777A–D'

AFSD

SVX9096

• Carefully release the cable (11) from the recess on
PC 1777.

When assembling, make sure that the:

• Cushion (12) is attached to the EMC filter (13).

• EMC filter (13) is placed into the support plate
recess.

• Retainer (14) is mounted correctly.

Backlight lamps

Using the Field Service System (FSS), a time meter
for the lamps can be shown. This time meter must be
reset after replacement of the lamps.

Type 1

aas

The Backlight lamp kit for TFT Display Type 1
includes two lamps. Always replace both lamps at
the same time.

To access the Backlight lamps:

• Lift off the TFT Display. Refer to section 'TFT
Display'.

• Remove the screws (1) holding the lamp.

• Lift off the lamp (2).

4

SVX9027

aas

SVX9097

d

Revision 05 Service Manual 4 - 9

Type 2

On TFT Display Type 2, only one Backlight lamp is
required.

To access the Backlight lamp:

• Lift off the TFT Display. Refer to section 'TFT
Display'.

• Release the snap-in holder and pull out the lamp.

• Lift off the lamp (3).

Disassembling and assembling SERVO-i Ventilator System

Touch screen including frame

The illustration shows Type 1, but the procedure for
Type 2 is the same.

To remove the Touch screen including frame (1):

• Lift off the TFT Display. Refer to section 'TFT
Display'.

• Remove the Main rotary dial (2):

– Pull off the Main rotary dial-knob.

– Remove the nut holding the Main rotary dial.

– Lift off the Main rotary dial.

• Remove the Direct access controls (3):

– Remove the cover on each Direct access

SVX9040

ads

4

control-knob.

– Loosen the nut on each knob and pull off the

knobs.

– Remove the nut holding each Direct access

control and lift off the controls.

Note: When mounting the Main rotary dial and the
Direct access controls on a new Touch screen incl.
frame, make sure that the knobs are easy to turn.

SVX9028

s

a

Label strips

The Touch screen including frame is delivered with
label strips in different languages, which have to be
mounted before the unit is taken into operation.
Protective foils (1) separate the adhesive areas
between the front panel film and the front panel.

Mount the label strips as follows:

• Select the two appropriate label strips:

– One label strip for the Fixed keys on the upper

right-hand area, and

– One label strip for the Special functions keys on

the lower right-hand area of the User Interface.

• Discard all other label strips.

Fixed keys label

• Insert the fixed keys label strip (2).

• Check its position through the button windows of
the front panel film. Adjust if necessary.

Align the label strip with great care. Once
installed the process cannot be reversed.

SVX9029

SVX9030

4 - 10 Service Manual Revision 05

SERVO-i Ventilator System Disassembling and assembling

• While holding the label strip in correct position,

d

remove the protective foils (3 and 4).

• Press the label strip against the adhesive area.

f

SVX9031

SVX9033

SVX9035

g

h

SVX9032

SVX9034

j

• Remove the protective foil (5).

• Press the front panel film (6) firmly against the front
panel to ensure proper adhesion.

4

Special functions keys label

• Insert the Special functions keys label strip (7).

• Check its position through the button windows of
the front panel film. Adjust if necessary.

Align the label strip with great care. Once
installed the process cannot be reversed.

k

• While holding the label strip in correct position,
remove the protective foils (8 and 9).

l

;

SVX9037

• Press the label strip against the adhesive area.

• Remove the protective foil (10).

• Press the front panel film (11) firmly against the
front panel to ensure proper adhesion.

SVX9036

A

SVX9038

Revision 05 Service Manual 4 - 11

SVX9039

Disassembling and assembling SERVO-i Ventilator System

Membrane foil

Note: The membrane foil (1) can only be replaced on

User Interface of Type 1.

SVX9125

4

SVX9126

SVX9127SVX9128

s

a

To replace the membrane foil:

• Separate the front panel section from the rear
cover. Refer to section User Interface.

• Disconnect the membrane foil connector (2) from
PC 1777.

• Remove the four Direct access knobs.

• Pull off the old membrane foil.

SVX9129

• Remove all remainings from the old membrane foil
on the User Interface front panel. Clean the area
for the membrane foil with ethanol or isopropanol.

SVX9130SVX9131

• Carefully separate the old membrane foil and
remove the label strip (3). The label strip must be
used on the new membrane foil.

Note: The label strip is not included in the
membrane foil spare part.

d

4 - 12 Service Manual Revision 05

SERVO-i Ventilator System Disassembling and assembling

When assembling the membrane foils adhesive
parts, align the parts with great care. Once
installed the process cannot be reversed.

• On the new membrane foil:

– Carefully remove the protective foil (4).

– Attach the front panel film (5) onto the membrane

button panel.

– Press the front panel film firmly against the

membrane button panel to ensure proper

SVX9132

adhesion.

gf

• Remove the two remaining protective foils (6).

• Place the label strip (3) in correct position.

4

SVX9133

SVX9134

hd

SVX9135SVX9127

SVX9136

kk

j

a

• Press the front panel film firmly against the
membrane button panel to ensure proper
adhesion.

• Remove the protective foils (7) and (8).

• Mount the membrane foil (1) onto the User
Interface front panel.

• Press the membrane foil firmly against the front
panel to ensure proper adhesion.

• Restore the User Inteface:

– Mount the four Direct access knobs.

– Connect the membrane foil connector to PC 1777.

Revision 05 Service Manual 4 - 13

Disassembling and assembling SERVO-i Ventilator System

Patient Unit

Front cover

sa

SVX9041

4

To remove the Patient Unit front cover (1):

• Remove the screw covers and the screws (2).

• Remove the two ventilation covers (3).

• Remove the two screws (4).

SVX9042

fd

SVX9043

d

f

• Carefully lift off the Patient Unit front cover (1).

Note: When assembling the unit, make sure that the
inspiratory and expiratory pressure transducer tubes
and the PC 1785 and expiratory valve coil cables are
not damaged by the Patient Unit front cover (1).

With power supply connected to the
SERVO-i, there are energized electrical
components inside the unit. All
personnel must exercise extreme
caution if fault tracing or adjustments
are performed with power supply connected and
with the Patient Unit front cover removed.

SVX9044

a

4 - 14 Service Manual Revision 05

SERVO-i Ventilator System Disassembling and assembling

PC 1771, PC 1772 and PC 1784

jhkfg

SVX9088

das

• Remove the Patient Unit front cover.

• PC 1771 Control (1):

– Release the locks on the PC board guides.

– Carefully pull out the PC board.

• PC 1772 Monitoring (2):

– Disconnect PC 1789 cable connector (3). This is

the cable for the optional PC 1789 Remote alarm
connector.

– Release the locks on the PC board guides.

– Carefully pull out the PC board.

• PC 1784 Expiratory channel (4):

– Disconnect pressure transducer tubes (5 and 6)

– Disconnect PC 1785 cable connector (7)

– Disconnect Exp. valve coil cable connector (8).

– Release the locks on the PC board guides.

– Carefully pull out the PC board.

Note: When replacing PC 1771 Control, PC 1772
Monitoring or PC 1784 Expiratory Channel, it can be
necessary to re-install the System SW. For further
information refer to section 'Replacing PC boards' in
this chapter.

On MR Environment approved units,
EMC absorbers are mounted on some
components on PC 1771, PC 1772 and
PC 1784.

4

SVX9076

SVX9075

fg

dd

AC/DC Converter

• Remove the Patient Unit front cover.

• Disconnect cable connectors (1 and 2).

• Remove the screws and nuts (3).

• Remove the screw (4).

• Carefully lift out the AC/DC Converter (5).

sa

Revision 05 Service Manual 4 - 15

Disassembling and assembling SERVO-i Ventilator System

Module unit including PC 1775 Plug-and-

agsf

play back-plane

• Remove the Patient Unit front cover.

• Remove the AC/DC Converter.

• Disconnect the nebulizer cable connector (1).

• Remove the screw (2).

• Remove the screws (3).

• Disconnect the Module unit/PC 1775 from PC
1770 Main back-plane at the connector (4).

• Carefully lift out the Module unit (5).

Note: When assembling the unit, make sure that the
spacer (6) is in position with its flat side facing down.
The spacer, designed as a wedge, should be pushed
inwards before the screws (3) are tightened.

4

dh

SVX9078 SVX9077

j

PC 1775 Plug-and-play back-plane is mounted on
the Module unit with the screws (7).

j

j

SVX9079

j

4 - 16 Service Manual Revision 05

SERVO-i Ventilator System Disassembling and assembling

Battery module locking device

• Lift off the Module unit to make the module locking
devices accessible.

• Carefully release and pull out the pin (1).

• Pull out the rod (2).

SVX9098

as

• Replace the old white locking device (3) with the
new blue (4).

4

SVX9099

SVX9101

SVX9103

d

SVX9100

f

• Place the rod and the locking device in correct
position. A tool. e.g. a hexagon wrench, is
required.

SVX9102

• Mount and secure the pin (1).

• Repeat the installation on all locking devices to be
replaced.

a

Revision 05 Service Manual 4 - 17

Disassembling and assembling SERVO-i Ventilator System

PC 1778 DC/DC & Standard connectors

• Remove the Patient Unit front cover.

• Remove the screws (1).

• Carefully pull out PC 1778 (2).

4

s

SVX9080

SVX9081

a

Internal fan

• Remove the AC/DC Converter.

• Remove PC 1789 Remote alarm connector if

a

d

mounted.

• Disconnect the fan cable connector (1).

• Remove the screws (2).

• Carefully lift out the Internal fan (3).

Note 1: When assembling units with metal air duct
(4), make sure that the rubber seal (5) is mounted as
shown in the illustration.

Note 2: An arrow on the fan housing indicates the air
flow direction. When mounting the fan, make sure
that the cooling air flow is directed into the unit.

g

s

f

SVX9082

4 - 18 Service Manual Revision 05

SVX9083

SERVO-i Ventilator System Disassembling and assembling

PC 1789 Remote alarm connector

PC 1789 Remote alarm connector is part of the
optional Alarm output connector.

• Disconnect the cable (1).

• Remove the screws (2).

• Carefully lift out PC 1789 (3).

SVX9073

a d

s

4

SVX9046

SVX9074

sa a

a

PC 1770 Main back-plane

• Remove PC 1780 Pneumatic back-plane (inside
the Inspiratory section).

• Remove:

– PC 1772 Monitoring

– PC 1771 Control

– PC 1784 Expiratory channel.

• Remove the AC/DC Converter.

• Remove the Module unit.

• Remove PC 1778 DC/DC & Standard connectors.

• Remove PC 1789 Remote alarm connector if
mounted.

• Remove the Internal fan.

• Remove the screws (1).

• Carefully lift out PC 1770 (2).

Note: The ventilators System ID, configuration,
operating time, etc, is stored in an EEPROM on
PC 1770 Main back-plane (2). Thus, when replacing
PC 1770, a spare part that is factory programmed for
the concerned ventilator must be used. For further
information refer to chapter 'Description of functions'.

Revision 05 Service Manual 4 - 19

Disassembling and assembling SERVO-i Ventilator System

Inspiratory channel

Removal of the inspiratory channel, as well as
removal of O2 Sensor and O2 cell/filter, is described
in the User's Manual.

Safety valve membrane

To remove the safety valve membrane:

• Remove the inspiratory channel.

• Release the latches (1), one on each side of the
safety valve housing, and lift off the membrane
holder (2).

4

SVX9047

a

sdf

• The membrane (3) and the valve seat (4) are now
accessible, e.g. for inspection and cleaning.

SVX9048

PC 1780 Pneumatic back-plane

To remove PC 1780:

• Remove the inspiratory channel including filter for
the inspiratory pressure transducer.

• Remove the screws (1).

• Carefully lift the mounting plate (2) and disconnect
the O2 Sensor/cell connector and the safety valve
pull magnet connector from PC 1780.

• Lift off the mounting plate (2). The safety valve pull
magnet is mounted on this plate.

• Pull out the gas modules to disconnect them from
PC 1780.

• Remove the threaded studs (3).

• Disconnect and lift off PC 1780 (4).

SVX9049

a

4 - 20 Service Manual Revision 05

s

SVX9050

d

f

Note: When assembling, the mounting plate (2) must
be adjusted to correspond with the inspiratory
channel latches.

SERVO-i Ventilator System Disassembling and assembling

Gas modules

To remove the gas modules:

• Remove the inspiratory section cover.

• Loosen the screw (1).

• Lift off the gas module bracket (2).

SVX9051

a

s

• Pull out and lift off both gas modules.

4

SVX9052SVX9053

ass

Note 1: When assembling, make sure that the
connector muff properly seals around the inspiratory
pipe (1). The connector muff must not be pushed too
far onto the nozzle units (2).

Note 2: The gas modules used in SERVO-i are
factory adjusted for this purpose. When replacing
gas modules, make sure to use only SERVO-i gas
modules. Similar gas modules intended for the
SERVO VENTILATOR 300/300A or KION/KION-i
Systems must not be used.

Revision 05 Service Manual 4 - 21

Disassembling and assembling SERVO-i Ventilator System

Gas module stabilizing bracket

The Gas module stabilizing bracket is included in the
SERVO-i Interhospital Transport Option Kit.

• Remove the upper cover on the inspiratory section
to make the gas modules available.

• Place the stabilization bracket (1) in position on the
gas modules. Mount the bracket with its two
screws.
The bracket will fill out the space between the gas
modules and the side walls. This will reduce gas
module vibrations and secure the modules
electrical connection.

SVX9104SVX9105

4

a

4 - 22 Service Manual Revision 05

SERVO-i Ventilator System Disassembling and assembling

PC 1785 Expiratory channel connector

f

s

d

a

SVX9054

To remove PC 1785:

• Remove the Patient Unit front cover.

• Disconnect the PC 1785 cable connector (1).

• Remove the screws (2).

• Pull down and lift off PC 1785 (3).

Note: When assembling, make sure that the rubber
seal (4) is correctly seated around PC 1785.

SVX9055

k

a

Expiratory valve coil

To remove the expiratory valve coil:

• Remove the Patient Unit front cover.

• Disconnect the connectors (2 and 3) from PC

1784.

• Disconnect the tubes (4 and 5) from PC 1784.

• Disconnect the inspiratory pressure tube from the
inspiratory pipe inside the inspiratory section (not
visible in this illustration).

• Remove the two screws (6).

• Lift off the cassette compartment (1).

df

hghs

4

jj

• Remove the screws (7).

• Lift off the expiratory valve coil (8).

j

SVX9056

Revision 05 Service Manual 4 - 23

Disassembling and assembling SERVO-i Ventilator System

Expiratory cassette membrane

The expiratory cassette is a complete unit and must

It is very important for the function of the
expiratory valve that the valve membrane is
removed and mounted correctly as described
below.

4

not be disassembled. The only part that can be
replaced is the valve membrane.

Operating capacity for the membrane is estimated to

10.000.000 breathing cycles. When this limit is
passed or if the membrane for some reason has
become defective, it must be replaced.

Remaining operating capacity (in %) for the
membrane can be shown in the Status window.
Select Status / Exp. cassette to check 'Remaining
membrane capacity'. The operating capacity meter
must be reset after replacement of the membrane.

Note: If the metal washer has been separated from
the membrane, it is important that the washer is
correctly mounted.

• Washers of old version have a raised hub (1) that
must be facing outwards as shown in the adjacent
illustration.

• Washers of new version do not have this raised
hub and can be mounted in both directions.

SVX9062

SVX9057

a

To remove the valve membrane from the cassette:

• Carefully remove the membrane including retaining
ring using a suitable retaining ring pliers.

To mount the valve membrane into the cassette:

• Place the retaining ring (2) correctly into the
membrane.

It is very important that the valve membrane and
the membrane seat in the cassette is clean. Dirt
particles can create leakage in the cassette.

s

SVX9058

4 - 24 Service Manual Revision 05

SERVO-i Ventilator System Disassembling and assembling

• Place the membrane onto the cassette as shown in
the illustration.

SVX9057

• Squeeze the retaining ring pliers and carefully
press the membrane in place into the cassette as
shown in the illustration.

4

SVX9059SVX9060

a

• Carefully release and remove the pliers.

• Check that the membrane is not deformed by the
retaining ring. If necessary, remove the membrane
and redo the complete mounting procedure.

• Mount the expiratory cassette onto the Patient
Unit.

• Reset the operating capacity meter after
replacement of the membrane. To access the reset
button, select Menu / Biomed / Service.

Expiratory one-way valve

To remove the expiratory one-way valve:

• Remove the Expiratory cassette membrane.

• Cut the one-way valves rubber lock (1) and make
sure to remove all valve parts.

To mount the expiratory one-way valve:

• Using a pair of pliers, pull the one-way valves
rubber lock (1) through its mounting hole in the
cassette. Make sure that the rubber lock is
correctly seated.

• Mount the Expiratory cassette membrane, refer to
instructions above.

Revision 05 Service Manual 4 - 25

Disassembling and assembling SERVO-i Ventilator System

Fixed Battery module

If any slot in the Module unit is equipped with a
locking device, a tool and two-hand operation is
required to remove the Battery module. To release
the fixed Battery module:

1. Push a suitable tool, e.g. a small hexagonal
wrench or a screwdriver, through the hole as
shown in the illustration.

2. At the same time, push the release button to the
right.

SVX9085

4

3. Remove the tool.

4. Continue to push the release button until the
Battery module snaps out.

5. Pull out the Battery module.

This locking device was previously not included in
the Module unit. To retrofit older units, the locking
device is available as spare part.

SVX9061

SVX9086

SVX9087

Control cable

The Control cable connectors must be connected
carefully to avoid damages on the connector pins.

• Carefully find the correct position; the connector

pins and the guides in the connectors must
correspond. Do not turn the connector while
inserting!

• When correct position is found, insert the

connector.

• Secure the connector with its locking ring.

The illustration shows the Patient Unit connector, but
the procedure for the User Interface connector is the
same.

Note: The Control cable must only be connected or
disconnected when the ventilator is switched Off.

On MR Environment approved units, two
ferrite blocks are mounted on the Control
cable.

4 - 26 Service Manual Revision 05

SERVO-i Ventilator System Service procedures

Only personnel trained and authorized
by MAQUET shall be permitted to
perform installation, service or
maintenance of the SERVO-i.

Make sure to prepare the SERVO-i properly
before disassembling and assembling. Refer to
section 'Hazard notices' in chapter 'Important'.

Any service or maintenance must be noted in a
log book.

After any installation, maintenance or service
intervention in the SERVO-i, perform a 'Pre-use
check'. Refer to the 'SERVO-i Ventilator System –
User's Manual' for details.

This product contains electronic and
electrical components. Discard
disposable, replaced and left-over parts
in accordance with appropriate
industrial and environmental standards.

5. Service procedures

Battery modules ................................................ 5 - 2

Replacing the lithium batteries on

PC 1771 and PC 1772 ...................................... 5 - 3

Using the Menu and Biomed key ..................... 5 - 4

Menu .............................................................. 5 - 4

Biomed ........................................................... 5 - 4

Manual leakage check ...................................... 5 - 6

General........................................................... 5 - 6

Parts tested during the check ....................... 5 - 6

Starting the Manual leakage check ............... 5 - 6

Test case 1 – Test tube ................................. 5 - 6

Test case 2 – Expiratory channel .................. 5 - 7

Test case 3 – Inspiratory channel .................. 5 - 8

Completing the Manual leakage check ......... 5 - 8

Software installation ......................................... 5 - 9

General........................................................... 5 - 9

Software information ..................................... 5 - 9

Software delivery ........................................... 5 - 9

Software installation procedure ..................... 5 - 9

Field Service System ........................................ 5 - 10

General........................................................... 5 - 10

Field Service System functions ..................... 5 - 10

5

Revision 05 Service Manual 5 - 1

Service procedures SERVO-i Ventilator System

5

The life span for the Battery module is calculated
to two and a half year from manufacturing date.
Normal time for logistics and storage are
included in this calculation. The calculation
corresponds thus to an estimated operational
time of two years. Manufacturing date (year­week) is printed on the battery label.

To guarantee safe battery backup, always use at
least two batteries.

Manufacturing

date = YYWW

(YearWeek)

Version 1 Version 2 Version 3

Batteri Module

Part No:. 64 87 180 E407E

Manufacturing Date: 0245
Hardware Version: xxxxx

SVX9106

SVX9107

SVX9108

Manufacturing Date :

Hardware Revision :

Batch No :

0420

xxxxx

xxxxx

Man. Date : 0520

S N xxxxx

Battery modules

System SW version V2.01.00 (or higher) includes an
improved monitoring of the battery status. Select
'Status / Batteries' on the User Interface to check
battery status. Refer to the illustrations below.

On ventilators with this improved battery monitoring,
the batteries condition and capacity are verified
during the Pre-use check and also continuously
during operation of the unit. No further functions
checks of the batteries are required.

With this improved battery monitoring, the Battery
status window shows:

• Usable backup time. Calculated as the sum of the

estimated backup time for the connected Battery
modules reduced with 10 minutes as an extra
safety feature.

• Slot number.

• Battery module S/N.

• Charge indicator for each battery, where:

0 boxes filled = < 10% relative charge
1 box filled = 10–25% relative charge
2 boxes filled = 26–50% relative charge
3 boxes filled = 51–75% relative charge
4 boxes filled = 76–100% relative charge

Recharge time for a discharged battery is approx.
3 hours/battery. If a battery is fully discharged, e.g.
due to long storage time, it may require up to 12
hours charging time.

With the charge status indicator on the User
Interface, the four green LEDs on the Battery
module are no longer required and will be removed
from the modules.

• Remaining operating time in minutes for each

battery.

Furthermore, an activity instruction, displayed
directly next to the operating time, may show:

• Expires soon. Message activated if expiry date will

be reached within 60 days.

• Replace battery. The battery must be replaced and

discarded. Message activated if:

– The batteries expiry date is passed and its life

span is exceeded. Note: Due to the age of the
battery, the calculated backup time may in this
case not be reliable. Even if the battery indicates
a significant backup time, the battery must be
replaced.

or

– The batteries operational capacity is too poor for

continued usage, caused e.g. by the chemical
process in an aging battery.

5 - 2 Service Manual Revision 05

SERVO-i Ventilator System Service procedures

Replacing the lithium batteries on PC 1771 and PC 1772

The lithium batteries must be replaced after 5 years.
A Technical error message will appear on the screen
if the battery voltage level is too low.

Always replace both batteries at the same time to
keep the same replacement date for both batteries.

Preparations

• Set the On/Off switch on the control unit to Off.

• Disconnect the mains power cable.

• Disconnect the gas supplies (wall and/or cylinder).

• Remove patient tubing.

Replacing the lithium battery

• The lithium batteries are mounted on ESD sensitive
PC boards. Refer to chapter 'Disassembling and
assembling', section 'Handling PC boards' for
further information regarding ESD sensitive
components.

• Remove the Patient Unit front cover. Refer to
chapter 'Disassembling and assembling'.

• Carefully pull out PC 1771 and PC 1772.

SVX9064

sd

a

f

Note: Do not remove the cable connector (1).
Information stored in the PC board memory will be
erased if the connector is removed:

– If the battery on PC 1771 is disconnected;

user default configurations made via the Field
Service System (FSS) and Pre-use check results
including transducer calibrations will be erased.

– If the battery on PC 1772 is disconnected;

all trends, all logs and Pre-use check results
including transducer calibrations will be erased.

• There are two equal battery connectors (2 and 3)
on the PC boards. Connect the new battery to the
un-used connector. The memory functions are now
secured by the new battery.

• Cut the cable ties holding the old battery (4) to the
PC board.

• Disconnect and remove the old battery.

• Mount the new battery onto the PC board using
new cable ties as shown in the illustration.

• Insert the PC board into the correct PC-board slot
and reassemble the Patient Unit.

After any maintenance or service of the SERVO-i,
perform a 'Pre-use check'. Refer to the 'SERVO-i
Ventilator System – User's Manual'.

5

Revision 05 Service Manual 5 - 3

Service procedures SERVO-i Ventilator System

Using the Menu and Biomed key

The 'Menu' and 'Biomed' functions are useful tools
during service.

The adjacent flowchart shows the 'Biomed' functions
in System version V4.0. A complete set of flowcharts
showing all 'Keys' and 'Screen touch pad' functions
can be found in the 'SERVO-i Ventilator System –
User's Manual'.

Menu

Pressing the fixed key 'Menu' will open the 'Menu
window' on the User Interface.

The 'Menu' is active in Standby and during ventilation
mode, but the available submenus differs.

Possible selections in the 'Menu' window are:

• Alarm

• Review

• Options

• Compensate

• Copy

• Biomed

• Panel lock

• Change patient category (only during ventilation).

Biomed

Submenu 'O2 cell adaptation' is active only during
ventilation modes in units with O2 cell. No access
code is required.

All other 'Biomed' submenus are available only
during Standby and requires an access code. The
default code is 1973, but the code can be changed
in the Biomed menu.

Service

Available only in Standby mode.

Event Log:

Displays Event logs. Useful during troubleshooting.

Service Log:

Displays Service logs. Useful during troubleshooting.

Report PM:

This button must be pressed when a Preventive
Maintenance has been performed. This will reset the
timer that indicates operating hours until next
Preventive Maintenance. Default value is 5,000 hours.
In the Report PM submenu, it is possible to enter a
new value, e.g. if the time stamp was erased during a
SW installation.

5

SVX9065

Biomed

Service

Event log

Service log

Report PM

Replaced Exp

membrane

configuration

sound level

Adult alarm

Infant alarm

Displayed

NIV adult

NIV infant

configuration

configuration

Set date

and clock

Change

access code

Start MCare

Remote Services

O

adaptation

Alarms

Ventilator settings

Functions

Latest

Time selection

Technical alarms

Test results

Preventive
Maintenance
Service report
history

Installation log

Latest

Time selection

Edit

Alarm

limits

limits

values

alarms

alarms

Startup

Copy

2 cell

Enter code 1973 to access the
Biomed menues.
The access code can be changed.

Display Event logs.

Possible selections:

• Latest logs

• Selected time interval

Display Service logs.

Possible selections:

• 21 latest logs

• Selected time interval

Enters date for a performed Preventive Maintenance
into the Service Log. Setting time stamp until next PM.

Reset of breath counter in expiratory cassette.

User default configuration setup.

Copy configuration to / from PC Card.

Date and time setup.

Change access code to Biomed menu.

Enable MCare Remote Services.

Measured O2 concentration will be adapted in
relation to set value.
Active only during ventilation, no access code required.

5 - 4 Service Manual Revision 05

SERVO-i Ventilator System Service procedures

Replaced Exp membrane:

This button must be pressed when the Expiratory
cassette membrane has been replaced. This will
reset the operating capacity meter (breath counter) in
the expiratory cassette.

Edit configuration

Available only in Standby mode.

Alarm sound level

Default alarm sound level can be changed in this
window.

Adult alarm limits and Infant alarm limits

Default invasive alarm limits can be changed in this
window:

• Pressure – Upper alarm limit

• Minute Volume – Lower and Upper alarm limit

• Respiratory Rate – Lower and Upper alarm limit

• End Exp. Pressure – Lower and Upper alarm limit

• End Tidal CO2 – Lower and Upper alarm limit

• Apnea time – Alarm limit.

Default configuration regarding 'General' and 'Units'
cannot be changed in this window. Access to the
Field Service System (FSS) is required.

Displayed values

The Measured value boxes on the User Interface
shows different parameters. Some of these
parameters are fixed and some are selectable in this
window.

NIV adult alarms and NIV infant alarms

Default NIV alarms can be changed in this window:

• Pressure – Upper alarm limit

• Minute Volume – Lower and Upper alarm limit

• Respiratory Rate – Lower and Upper alarm limit

• End Exp. Pressure – Lower and Upper alarm limit

• CPAP – Lower and Upper alarm limit (infant alarm)

• End Tidal CO2 – Lower and Upper alarm limit

• Apnea time – Alarm limit (infant alarm).

The alarms listed above, except Pressure alarm and
Apnea time alarm, can be permanently silenced in
this window.

Default configuration regarding 'General' and 'Units'
cannot be changed in this window. Access to the
Field Service System (FSS) is required.

Startup configuration

Requires Software Version 3. Startup configuration
can be changed in this window:

• Patient range

• Type of ventilation

• Volume setting

• Breath Cycle setting

• Pre/post oxygenation conc. above set O2 conc

• Option to deactivate backup ventilation.

Copy configuration

Available only in Standby mode.

Default user configuration can be copied to / from a
PC Card.

Default configuration regarding 'General', 'Units' and
'Alarm limits' will be copied.

Useful when applying the same user configuration on
a number of units.

Set date and clock

Available only in Standby mode.

Date and time setting can be changed in this
window.

Change access code

Available only in Standby mode.

Access code to the 'Biomed' menu can be changed
in this window.

Start MCare Remote Services

Available only in Standby mode.

Will enable MCare Remote Services.

Refer to separate MCare Remote Services
documentation for further information.

O2 cell adaptation

Available only during ventilation in units with O2 cell.
No access code required.

Adjustment of the O2 concentration reading.

Refer to the 'SERVO-i Ventilator System – User's
Manual', for further information.

5

Revision 05 Service Manual 5 - 5

Service procedures SERVO-i Ventilator System

Manual leakage check

General

When a leakage is detected in the internal leakage
test, the Pre-use check will stop and display either
'Leakage' or 'Excessive leakage'. To locate the
leakage, the three leakage tests described below
can be used.

The check requires:

• Leakage detector, P/N 65 03 721

• Calibration manometer, P/N 61 03 527

Parts tested during the check

Test case 1 – Test tube:

• Test tube

Test case 2 – Expiratory channel:

• Expiratory inlet incl. moisture trap with O-ring

• Expiratory cassette

• Expiratory valve membrane

• Expiratory pressure transducer tube

5

• Expiratory pressure transducer

• Expiratory valve coil.

Test case 3 – Inspiratory channel:

• Nozzle units in gas modules

• Silicone connector muff between gas modules and
inspiratory pipe.

• Inspiratory pipe

•O2 cell bacteria filter seal

• Safety valve membrane

• Inspiratory pressure silicone tube

• Inspiratory pressure bacteria filter

• Inspiratory bacteria filter holder incl. tube (grey)

• Inspiratory pressure transducer.

Starting the Manual leakage check

Start the manual leakage check when the Pre-use
check has stopped and displayed either 'Leakage' or
'Excessive leakage'. Do not cancel the Pre-use
check, the 'Redo test' function will be used during
the manual leakage check.

SVX9112

Test case 1 – Test tube

1. Check the blue test tube for leakage. Replace if
required.

2. Reconnect the blue test tube properly.

3. Select 'Redo test'.

If the leakage remains, continue with Test case 2.

SVX9139

5 - 6 Service Manual Revision 05

SERVO-i Ventilator System Service procedures

Test case 2 – Expiratory channel

Expiratory inlet
including moisture
trap with O-ring

Expiratory cassette

PC1786

H
B

PC1785

A

Expiratory
valve
membrane

Leakage
detector

Calibration
manometer

SVX9146

2.1 Expiratory channel

1. Connect leakage detector and manometer at
expiratory inlet.

2. Select 'Redo test'.

3. When the expiratory valve closes, pressurize to
approx. 80 cmH2O. This must be done quickly
because the expiratory valve coil is closed only
for 2-3 seconds. A pressure drop indicates a
leakage.

If a leakage is detected in 2.1 Expiratory channel,
continue with 2.2 Expiratory valve coil.
If not, go to Test case 3.

2.2 Expiratory valve coil

1. Remove the expiratory cassette.

2. Select 'Redo test'.

3. Make sure the expiratory valve coil axis is
activated (pushed up).

If the axis is activated, continue with 2.3 Expiratory
cassette.
If not, check/replace as follows (one at a time):

• Check the expiratory valve coil including cable and

connector.

• Replace PC 1784 Expiratory Channel.

• Replace PC 1771 Control.

PC1784

Expiratory
pressure
transducer

Expiratory pressure
transducer tube

PC 1781

P50

MOD1

P40 N40

Expiratory
valve coil

PC1785

2.3 Expiratory cassette

1. Connect the leakage detector and manometer to
the expiratory inlet (while the cassette is
removed).

2. Block the expiratory pressure transducer channel
hole on the cassette and close the expiratory
valve by hand, see illustration below.

SVX9111

3. Pressurize to approx. 80 cmH2O. If a leakage is
detected check/replace the following parts (one
at a time):

• Expiratory inlet incl. moisture trap with O-ring.

• Expiratory valve membrane. The membrane

may not close properly due to cleaning
residues on the membranes sealing surface
and/or on the corresponding sealing surface in
the cassette.

• Expiratory cassette.

2.4 Expiratory pressure transducer and tube

1. If a leakage is detected in the Expiratory channel
but still remains after performed tests 2.2–2.3,
check the Expiratory pressure transducer and
Expiratory pressure transducer tube.

5

Revision 05 Service Manual 5 - 7

Service procedures SERVO-i Ventilator System

Test case 3 – Inspiratory channel

Inspiratory
pressure
silicone
tube

Safety valve
membrane

5

SVX9147

Test case 3

Leakage
detector

Inspiratory
outlet

Calibration
manometer

1. Connect the leakage detector and manometer to
the inspiratory outlet.

2. Pressurize to approx. 80 cmH2O. A pressure
drop indicates a leakage. Check/replace the
following parts:

• Silicone connector muff.

• Inspiratory pipe.

•O2 cell bacteria filter seal.

• Safety valve membrane.

• Inspiratory pressure silicone tube.

• Inspiratory pressure bacteria filter.

3. Pressurize as described in step 2. If the leakage
remains, check/replace:

• Nozzle units in the gas modules.

4. Pressurize as described in step 2. If the leakage
remains, check/replace:

• Inspiratory bacteria filter holder incl. tube.

• Inspiratory pressure transducer.

Inspiratory pipe

N17
P17

PC1781

P50

MOD2

O2 Cell

or

O2 Sensor

Inspiratory
pressure
transducer

O2 cell
bacteria
filter seal

N18

P18

Inspiratory
pressure
bacteria
filter

Inspiratory bacteria
filter holder incl. tube

PC1784

Silicone
connector
muff

Nozzle
unit
in gas
module

Nozzle
unit
in gas
module

Gas

Module

O

2

Gas

Module

AIR

Completing the Manual leakage check

1. Restore the unit including blue test tube.

2. Select 'Redo test' and make sure the test
passes.

5 - 8 Service Manual Revision 05

SERVO-i Ventilator System Service procedures

Software installation

General

• Before starting any SW Upgrade or Update, check:

– Installed System SW version (see 'System SW

version' in the Status / General window)

– System SW version stored on the PC Card.

It is not recommended to install System SW with
lower version number than already installed in the
SERVO Ventilator System.

• If an Edi Module is part of the system, make sure
that this module is connected during software
installation. Software stored in the module will be
checked/updated during the software installation.

• After any installation, maintenance or service
intervention in the SERVO-i, perform a 'Pre-use
check' according to instructions in the 'SERVO-i
Ventilator System – User's Manual'.

Software information

There are two different intentions for software
installation:

SW Update

A SW Update will install a new System SW version in
the SERVO Ventilator System. SW Updates are not
dependent on the serial number of the ventilator and
will not alter the installed SW Options.

SW Upgrade

A SW Upgrade will change the function of the
SERVO Ventilator System. A SW Upgrade is
individually created for each ventilator and can only
be installed on this ventilator. S/N of the ventilator
must be stated when ordering a SW Upgrade.

SW Upgrade

SW Update

SW Option

SW Option

SW Option

SW Option

Option Upgrade

All System versions

SW Option

Major

function

improvement

Software Version

System version V3.0 or higher

Corrections

and minor

function

improvement

SW Service Release

ServoS-9105

System version V3.0 or higher

Software delivery

SW Updates and SW Upgrades can be downloaded
from the 'MCC SW Download' website or delivered
via freight on a PC Card.

• SW Updates are not dependent on the S/N of the
ventilator and can thus be installed on any unit.

• SW Upgrades are specific for each ventilator and
can only be installed on this unit. SW Upgrades
must thus be ordered and created in factory before
they can be available on the website or delivered
on a PC Card.

System SW Update

System version V1.0 - V2.1

5

Software installation procedure

Further information regarding the different softwares
and the software installation procedure can be found
in the 'SERVO-i / SERVO-s Software – Installation
Instructions'.

Revision 05 Service Manual 5 - 9

Service procedures SERVO-i Ventilator System

Field Service System

General

• The Field Service System (FSS) is a software
provided to facilitate troubleshooting, service and
maintenance of the SERVO Ventilator System.

• To access the Field Service System, a Service card
(PC Card) and an access code must be used.
The access code is unique for each Service card.

• The Service card is personal and must not be
handed-over to anyone else.

• It is only possible to access the Field Service
System with the ventilator in Standby mode.

• The Field Service System must not be activated
with a patient connected the ventilator.

Field Service System functions

In the Field Service System, it is possible to:

• Display information regarding the ventilator
including options and parts installed.

• Calibrate the internal barometer.

• Display service and event logs.

5

• Run complete or selected test sequences.

• Create and save service reports.

• Export selected logs to a PC Card.

• Create user default configurations.

• Disable the Preventive Maintenance notification.

5 - 10 Service Manual Revision 05

SERVO-i Ventilator System Troubleshooting

Only personnel trained and authorized
by MAQUET shall be permitted to
perform installation, service or
maintenance of the SERVO-i.

Make sure to prepare the SERVO-i properly
before disassembling and assembling. Refer to
section 'Hazard notices' in chapter 'Important'.

Any service or maintenance must be noted in a
log book.

After any installation, maintenance or service
intervention in the SERVO-i, perform a 'Pre-use
check'. Refer to the 'SERVO-i Ventilator System –
User's Manual' for details.

This product contains electronic and
electrical components. Discard
disposable, replaced and left-over parts
in accordance with appropriate
industrial and environmental standards.

6. Troubleshooting

General.............................................................. 6 - 2

Pre-use check ................................................... 6 - 3

Technical error codes and messages............... 6 - 11

6

Revision 05 Service Manual 6 - 1

Troubleshooting SERVO-i Ventilator System

Possible causes to malfunction not mentioned
in the following troubleshooting guides are:

• The system has not been correctly
assembled after cleaning, maintenance or
service.

• Disconnection or bad connection in cable
connectors, PC board connectors, and
interconnection boards.

• Disconnected or defective gas tubes.

These possible causes to malfunction must
always be considered during troubleshooting.

General

Before starting troubleshooting, try to eliminate all
possibilities of operational errors. If the malfunction
remains, use the troubleshooting guides below as
well as the information in chapter 'Description of
functions' to locate the faulty part. Perform actions
step by step and check that the malfunction is
eliminated.

When the fault is corrected, carry out a complete
'Pre-use check' as described in the 'SERVO-i
Ventilator System – User's Manual'.

The troubleshooting guides below are focused only
on technical problems. Information about clinical
related problems can be found in the 'SERVO-i
Ventilator System – User's Manual'.

For functionality enhancement, the latest released
System SW version is always recommended.

The Information in this chapter applies to System
version V4.0 (or higher).

6

6 - 2 Service Manual Revision 05

SERVO-i Ventilator System Troubleshooting

Pre-use check

The SERVO-i demands the user to start the
automatic Pre-use check at every startup of the unit.
It is also possible to select the Pre-use check via the
Standby menu.

The 'SERVO-i Ventilator System – User's Manual'
describes how to perform this Pre-use check. The
Pre-use check-description on the following pages
gives more detailed information about the Pre-use
check. This information can be used e.g. during
troubleshooting of the unit.

* Text within brackets refers to the tested subsystem; BRE = Breathing, MON = Monitoring, PAN = Panel.

Test Test description * Recommended action if the test fails

During system start­up.

Internal technical tests:

•

SW check

•

Reading EEPROM

•

Checksum EEPROM

•

Panel button stuck test

•

Audio test.

(BRE + MON + PAN)

Some of the recommended actions described below
refer to the Field Service System (FSS). The Service
card is required to access the FSS. Troubleshooting
can of course be performed without access to the
FSS, but for some of the recommended actions, the
FSS will make troubleshooting faster and easier.

Check if the fault remains after each performed
service action. Re-run the complete Pre-use check
or run the concerned test using the FSS.

Via the standby menu it is possible to perform a
separate Patient circuit test to evaluate circuit
leakage and measure circuit compliance. This
separate test does not replace the complete pre-use
check

1. Restart the unit. Do not touch the

User Interface during system start­up. Interfering with the knobs,
keys, touch screen, loudspeaker
grid, etc, may affect the internal
technical tests.

2. Reinstall the System SW.

6

Start Pre-use check

Internal tests

Revision 05 Service Manual 6 - 3

Audio test.

(MON + PAN)

Alarm output connector test.

Performed only if this option is
installed.

(MON)

Power failure test.

(MON)

If possible, check the ‘Test results’-log
in the ‘More detailed’ mode (FSS).

If the audio test failed:

1. Make sure that the Patient Unit

main cover and the User Interface
rear cover are correctly mounted.
Otherwise the audio tests may fail.

2. Check in the Test results-log (FSS)

if it was the Panel test or the
Monitoring test that failed:

• If the Monitoring test failed:

Replace PC 1772 Monitoring.

• If the Panel test failed:

Replace the loudspeaker or
PC 1777 Panel.

Troubleshooting SERVO-i Ventilator System

Test Test description * Recommended action if the test fails

Internal tests
(continued)

Barometer test Checks that the barometric pressure

measured by the internal barometer is
within 630–1080 hPa.

Checks that the measured barometric
pressure values differs less than 8 hPa
between BRE and MON.

(BRE + MON)

If the Alarm output connector test
failed:

1. Replace PC 1789 Remote alarm

connector.

2. Replace PC 1772 Monitoring

If the power test failed:

1. Replace PC 1772 Monitoring.

Check the Barometric pressure value in
the Status window:

If that value is within 630–1080 hPa:

1. Replace PC 1771 Control

2. Replace PC 1772 Monitoring

3. Replace PC 1784 Expiratory

channel

4. Replace the gas modules. Replace

one gas module at a time.

If that value is outside 630–1080 hPa:

6

Gas supply test The test will start with a 14 s gas flush

for Gas type detection:

1. If Air or Heliox is used.

2. That approved Heliox mixture is

used.

3. That the Heliox option is enabled

(if Heliox gas is detected).

Checks that the gas supply pressures
measured by the internal gas supply
pressure transducers are within:

1. Air and O

: 200–650 kPa (2.0–6.5

2

bar).

2. Heliox: 200–350 kPa (2.0–3.5 bar).

Checks that the measured supply gas
pressure values differs less than
20 mbar between MON and BRE.

(BRE + MON)

1. Replace PC 1772 Monitoring.

If the Gas type detection fails:

1. Check that the connected gases

are within specified range.

2. If Heliox is used, check that the

Heliox option is installed.

If the gas supply pressure test fails:

1. Check that the connected gas

supply pressure is within the
specified range.

2. Start the unit in a ventilation mode

and check the alarms:

• If an Air supply pressure-alarm

is activated, replace the Gas
module Air.
Note: If Heliox is used:
– Replace the Heliox adapter.
– Replace the Gas module Air.

• If an O

supply pressure-alarm

2

is activated, replace the Gas
module O

.

2

3. Replace PC 1771 Control.

4. Replace PC 1772 Monitoring.

6 - 4 Service Manual Revision 05

SERVO-i Ventilator System Troubleshooting

Test Test description * Recommended action if the test fails

Internal leakage test Checks the internal leakage, with test

tube connected, using the inspiratory
and expiratory pressure transducers.

Checks that the leakage at 80 cm H
is max. 10 ml/min.

Checks that the measured pressure
values differs less than 5 cm H
between Insp. and Exp.

(BRE)

2

O

2

The ‘Manual leakage check’, described
in chapter ‘Service procedures’ can be
used to locate the leakage.
The ‘Manual leakage check’ is a

O

complement to the recommended
actions below.

If message ‘Leakage’ or ‘Excessive
leakage’ appears:

1. Check that the test tube is

correctly connected.

2. Check the expiratory cassette:

• Check that the cassette is

correctly seated in the cassette
compartment.

• If possible, replace the

expiratory cassette and check if
the new cassette is accepted by
the Pre-use check.

• If the new cassette was

accepted by the Pre-use check,
the fault was located to the
cassette. To repair the old
cassette, check that the
expiratory valve membrane is
clean and correctly seated in
the cassette. Replace the
membrane if required.

3. Check that the pressure transducer

tubes/filters are correctly mounted.

6

4. Check the inspiratory section:

• Check that the inspiratory pipe

is correctly mounted in the
inspiratory section.

• Check that the safety valve

membrane is clean and
correctly seated in the
inspiratory pipe.

• Check that the safety valve

closes properly when the Pre­use check is started (distinct
clicking sound from the valve).
If the safety valve opens during
this test, the opening pressure
may not be correctly calibrated
(see ‘Safety valve test’ below).
Run the ’Safety valve test’ and
repeat the complete Pre-use
check.

Revision 05 Service Manual 6 - 5

Troubleshooting SERVO-i Ventilator System

Test Test description * Recommended action if the test fails

Internal leakage test
(continued)

If message ‘Pressure Transducer

difference > 5 cm H

1. Check that the pressure transducer

tubes and the inspiratory filter are
correctly mounted.

2. Check that both PC 1781 Pressure

transducer (Insp. and Exp.) are
correctly mounted.

3. If the ‘Pressure transducer test’

also fails (see below), refer to the
recommended actions if ‘Pressure
transducer test’ failed.

If message ‘System volume too small’
appears:

1. Replace the gas modules. Replace

one gas module at a time.

If message ‘System volume too large’
appears:

1. Check that the correct test tube is

used during the Pre-use check.

O’ appears:

2

6

2. If the ‘Flow transducer test’ also

fails (see below), replace the gas
modules. Replace one gas module
at a time.

3. Refer to troubleshooting as

described for ‘Leakage’ or
‘Excessive leakage’ above.

6 - 6 Service Manual Revision 05

SERVO-i Ventilator System Troubleshooting

Test Test description * Recommended action if the test fails

Pressure transducer
test

Calibrates and checks the inspiratory
and expiratory pressure transducers.

The new zero value for the pressure
transducers may not differ more than
±6 cm H

With the inspiratory pressure
transducers used as a reference, a new
gain factor is set for the expiratory
pressure transducer. The new gain
factor may not differ more than ±5%
from factory calibration.

During this test, the different
subsystems concerned are compared.
The difference between the sub­systems must not be more than
±1 cm H

Expiratory valve coil test. Measures
offset and gain in the valve coil.

(BRE + MON)

O from factory calibration.

2

O at 60 cm H2O.

2

Check that System SW V1.03.01 (or
later) is installed. Update System SW if
required.

Check the ‘Test results’-log in the
‘More detailed’ mode. (FSS)

If ‘Pressure transducer test’ failed:

1. Check the expiratory cassette:

• If possible, replace the

expiratory cassette and check if
the new cassette is accepted by
the Pre-use check.

• If the new cassette was

accepted by the Pre-use check,
the fault was located to the
cassette.
The fail with the old cassette
may in this case be due to water
collected at the pressure
transducer filter inside the
cassette. Dry the old cassette
properly.

2. Check/replace PC 1781 Pressure

transducer (Insp. and Exp.).
To locate the faulty pressure
transducer, replace one transducer
at a time.

3. Replace PC 1771 Control.

6

4. Replace PC 1772 Monitoring.

If ‘Expiration valve test’ failed:

1. Check the expiratory cassette:

• If possible, replace the

expiratory cassette and check if
the new cassette is accepted by
the Pre-use check.

• If the new cassette was

accepted by the Pre-use check,
the fault was located to the
cassette. To repair the old
cassette, check that the
expiratory valve membrane is
clean and correctly seated in
the cassette. Replace the
membrane if required.

2. Replace the Expiratory valve coil.

Revision 05 Service Manual 6 - 7

Troubleshooting SERVO-i Ventilator System

Test Test description * Recommended action if the test fails

6

Safety valve test Checks and if necessary adjusts the

opening pressure for the safety valve to
117 ±3 cm H

O.

2

Checks the hardware signals related to
the safety valve functions.

(BRE + MON)

O2 cell/sensor test Calibrates and checks the O2 Sensor/

cell at 21% O

Checks if the O

and 100% O2.

2

cell is worn out.

2

As different gas mixtures are used
during this test, calibration and check

Sensor/cell will not be performed

of O

2

if one gas is missing.

The O

Sensor test requires 21% O2

2

and 100% O
used (e.g. O
instead of 100%) the O

. If other gas mixtures are

2

supply delivers 96% O2

2

cell/sensor test

2

may fail.

1. Check the inspiratory section:

• Check that the inspiratory pipe

is correctly mounted in
inspiratory section.

• Check that the safety valve

membrane is clean and
correctly seated in the
inspiratory pipe.

2. Replace the safety valve pull

magnet.

3. Replace PC 1784 Expiratory

channel.

4. Replace PC 1772 Monitoring.

1. Check that the connected gas

supply pressure (Air and O

) is

2

within the specified range.

2. Replace the O

Sensor/cell.

2

3. Replace the gas modules. Replace

one gas module at a time.

4. Replace PC 1771 Control.

5. Replace PC 1772 Monitoring.

(BRE + MON)

6 - 8 Service Manual Revision 05

SERVO-i Ventilator System Troubleshooting

Test Test description * Recommended action if the test fails

Flow transducer test

Checks the inspiratory flow transducer.
Calibrates and checks the expiratory
flow transducer.

Calibrates at 60% O
100% and 21% O

and checks at

2

. As different gas

2

mixtures are used during this test,
calibration of the expiratory flow
transducer will only be performed if
both gases are connected. The check
using the connected gas, (100% alt.
21% O

) will however be performed.

2

The ‘Flow transducer test’ will pass if
the result of this check corresponds to
the old calibration factor from a
previous Pre-use check. The same
expiratory cassette must be used.

The new calibration factor for the
expiratory flow transducer may not
differ more than -10% to +15% from
factory calibration.

During this test, the different
subsystems concerned are compared.
The difference between the
subsystems must not be more than
±0.3 l/min.

(BRE + MON)

1. Check that the connected gas

supply pressure (Air and O

) is

2

within the specified range.

2. Check the expiratory cassette:

• Check that the cassette is

correctly seated in the cassette
compartment.

• If possible, replace the

expiratory cassette and check if
the new cassette is accepted by
the Pre-use check.

• If the new cassette was

accepted by the Pre-use check,
the fault was located to the
cassette.
The fail with the old cassette
may in this case be due to water
collected inside the cassette.
Dry the old cassette properly.

3. Replace the gas modules. Replace

one gas module at a time.

4. Replace PC 1785 Expiratory

channel connector.

5. Replace PC 1771 Control.

Battery switch test Checks that the power supply switches

to battery when mains power is
disconnected.

Checks that the power supply switches
back to mains power when re­connected.

This test will not be performed if:

• Less than 10 min. backup time

remains in the connected Battery
module(s).

• No Battery module is connected.

(MON)

6. Replace PC 1772 Monitoring.

7. Replace PC 1784 Expiratory

channel.

1. Check that the total remaining time

for the Battery module(s) is >10
min. If not, allow the battery to
charge and repeat the test.

2. Replace PC1775 Plug-and-play

back-plane.

3. Replace the Battery module(s).

6

Revision 05 Service Manual 6 - 9

Troubleshooting SERVO-i Ventilator System

Test Test description * Recommended action if the test fails

6

Patient circuit test

Y Sensor test

Alarm state test Checks that no Technical error alarms

External alarm system
test

Checks the patient circuit leakage, with
patient tubing connected, using the
inspiratory and expiratory pressure
transducers.

Checks that the leakage at 50 cm H
is max. 80 ml/min.

Will allow the system to calculate a
compensation for circuit compliance
(if the leakage requirements are met).

(BRE)

Checks the pressure and flow
measurement of the Y Sensor.

This test is only performed is a Y
Sensor and a Y Sensor module is
connected to the system.

are active during the Pre-use check.

(MON)

If the option Alarm Output Connector is
enabled, the user can test the external
alarm system.

The external alarm output signal is
activated and the user must verify the
external alarm.

2

O

If the internal leakage test (see above)
has passed, the leakage is to be
located to the patient circuit. Check for
leakage or replace the patient circuit.

1. If the patient circuit test (see above)

has passed, check that there is no
leakage in the Y Sensor and that
there are no obstructions in the Y
Sensor tubing’s.

2. Replace the Y Sensor.

3. Replace the Y Sensor Module.

Refer to section regarding Technical
error alarms for further information.

1. Check the external alarm system.

2. Replace PC 1789 Remote alarm

connector.

The result of the test does not affect
the outcome of the Pre-use check

Test Test description * Recommended action if the test fails

Separate Patient
circuit test.

6 - 10 Service Manual Revision 05

This test separately performs the
Patient circuit test as described above.

If a Y Sensor and a Y Sensor Module
are connected to the system, the
Y Sensor test is also performed (as
described above).

See above

SERVO-i Ventilator System Troubleshooting

Technical error codes and messages

The table below shows recommended actions in
case of Technical errors.

Error
code

Error message / Possible cause Recommended action

Monitoring

1 Power failure.

-12 V too low, i.e. < -13.2 V.

2 Power failure.

-12 V too high, i.e. > -10.8 V.

3 Power failure.

+12 V too low, i.e. < +10.8 V.

Some of the Error codes are intended only for
R&D, not for field service. If so, the text ‘N/A’ is
stated in the ‘Recommended action’-column.

1. Replace PC 1778 DC/DC & Standard

Connectors.

1. Check status of external battery

(if connected).

2. Replace PC 1778 DC/DC & Standard

Connectors.

3. Replace PC 1775 Plug-and-play back-plane.

1. Check status of external battery

(if connected).

2. Replace PC 1778 DC/DC & Standard

Connectors.

4 Power failure.

+12 V too high, i.e. > +13.2 V.

5 Power failure.

+24 V too low, i.e. < 21.5 V.

6 Power failure.

+24 V too high, i.e. > 26.5 V.

7 Patient category error.

Patient category mismatch between
Breathing and Monitoring subsystems.

8 Insp. pause hold time exceeded.

The max. ‘Insp. pause hold time’ 30 s
exceeded. The system has not returned to
ventilation after ‘Insp. pause hold time’.

3. Replace PC 1775 Plug-and-play back-plane.

1. Replace PC 1778 DC/DC & Standard

Connectors.

1. Replace PC 1778 DC/DC & Standard

Connectors.

2. Replace the gas modules. Replace one gas

module at a time and check that this
technical error code will not appear.

1. Replace PC 1778 DC/DC & Standard

Connectors.

1. Replace PC 1771 Control.

2. Replace PC 1772 Monitoring.

3. Replace the gas modules. Replace one gas

module at a time and check that this
technical error code will not appear.

1. Replace PC 1771 Control.

6

Revision 05 Service Manual 6 - 11

Troubleshooting SERVO-i Ventilator System

Error
code

Error message / Possible cause Recommended action

The max. ‘Exp. pause hold time’ 30 s
exceeded. The system has not returned to
ventilation after ‘Exp. pause hold time’.

10 Ventilation stopped.

The ‘VALVES_DISABLED’ signal has stopped
power supply to gas modules and safety
valve.

11 Safety valve open.

The Safety valve is detected as open without
fulfilled opening conditions.

PC 1771 Control failure. Communication with
PC 1772 Monitoring lost due to SW or HW
failure.

1. Replace PC 1771 Control. 9 Exp. pause hold time exceeded.

1. Replace PC 1784 Expiratory channel.

2. Replace PC 1771 Control.

3. Replace PC 1778 DC/DC & Standard

Connectors.

4. Replace PC 1772 Monitoring.

1. Check inspiratory channel.

2. Replace safety valve pull magnet.

3. Replace PC 1784 Expiratory channel.

Note: If the Patient Unit is placed too close to
the MR scanner, this error may be activated.

1. Replace PC 1771 Control. 12 Ventilation stopped.

6

13 Ventilation stopped.

Software conflict. Two PC 1771 Control
detected on the CAN bus.

14 User Interface communication failure.

Communication interference between
PC 1777 Panel and PC 1772 Monitoring.

This Error code in not used on System
version V1.2 or later, but message “Restart
ventilator” is still shown on the display (if the
display works).

15 Ventilation stopped.

Software conflict. Two PC 1777 Panel
detected on the CAN bus.

PC 1784 Expiratory channel failure.

17 Ventilation stopped.

Software conflict. Two PC 1784 Expiratory
channel detected on the CAN bus.

N/A

1. Check the control cable

2. Replace PC 1777 Panel.

3. Replace PC 1778 DC/DC & Standard

Connectors.

Note: This error indicates communication failure
between PC 1777 and PC 1772 and the error
code may thus not be shown on the display (but
will be logged).

N/A

1. Replace PC 1784 Expiratory channel. 16 Ventilation failure.

N/A

6 - 12 Service Manual Revision 05

SERVO-i Ventilator System Troubleshooting

Error
code

Error message / Possible cause

Backup alarm buzzer failure.

24 Backup alarm or Remote alarm failure.

Failure indicated in the backup alarm or
remote alarm capacitor on PC 1772
Monitoring.

25 Communication failure.

Communication failure between
ID PROMs/EEPOTs and Monitoring
subsystem.

Recommended action

1. Replace PC 1772 Monitoring. 22 Backup alarm failure.

1. Make sure that System SW version V3.02.02

(or later) is installed.

2. Replace PC 1772 Monitoring

Depending on ID # stated in the Technical alarm
log.

If repeated, replace parts as follows:

0: Report to MCC HSC / MAQUET for further

information.

1: PC 1772 Monitoring.

2: PC 1775 Plug-and-play back-plane.

3: PC 1778 DC/DC & Standard Connectors.

4: PC 1781 Inspiratory pressure transducer.

5: PC 1781 Expiratory pressure transducer.

27 Backup alarm failure.

Backup alarm buzzer failure.

28 Audible alarm failure.

Loudspeaker failure.

29 Lithium battery depleted.

The lithium battery on PC 1772 Monitoring is
depleted.

6: O

32: PC 1784 Expiratory channel or PC 1772

33: Gas module Air or PC 1772 Monitoring.

34: Gas module O2 or PC 1772 Monitoring.

35: PC 1772 Monitoring.

256: PC 1771 Control.

512: PC 1777 Panel.

784: N/A

1. Replace PC 1772 Monitoring.

Note: If the Patient Unit front cover is removed,
this error may be activated.

1. Replace the loudspeaker.

2. Replace PC 1777 Panel.

Note: If the User Interface rear cover is removed,
this error may be activated.

1. Replace lithium battery on PC 1772

Sensor/cell or O2 Sensor/cell cable or

2

PC 1772 Monitoring.

Monitoring.

Monitoring.

6

Revision 05 Service Manual 6 - 13

Troubleshooting SERVO-i Ventilator System

Error
code

Error message / Possible cause Recommended action

32 Software version conflict.

Conflict between the software versions
installed.

Communication failure or PC 1771 Control
failure during startup.

34 User Interface communication failure.

Communication failure between PC 1777
Panel and PC 1772 Monitoring during startup.

35 Ventilation disabled.

Communication failure or PC 1784 Expiratory
channel failure during startup.

N/A

1. Replace PC 1771 Control. 33 Ventilation disabled.

1. Check the control cable.

2. Replace PC 1778 DC/DC & Standard

Connectors.

3. Replace PC 1777 Panel.

Note: This error indicates communication failure
between PC 1777 and PC 1772 and the error
code will thus not be shown on the display (but
will be logged).

1. Replace PC 1771 Control (if logged after

error code 40001).

2. Replace PC 1784 Expiratory channel.

6

May appear at the first startup after a
software installation (restart required).

37 Patient category failure.

Patient category mismatch between
Breathing and Monitoring subsystems.

38 Atmospheric pressure too high.

Atmospheric pressure above allowed limit or
barometer failure.

39 Atmospheric pressure too low.

Atmospheric pressure below allowed limit or
barometer failure.

Invalid measured metric detected (Ppeak,
MVe or RR). The invalid metric is not
displayed.

41 Real time clock failure.

Internal processor real time clock failure.

N/A

1. Adjust barometer (FSS required).

2. Replace PC 1772 Monitoring.

1. Adjust barometer (FSS required).

2. Replace PC 1772 Monitoring.

Note: This alarm will be activated if the ambient
pressure is below 650 hPa, e.g. on a high
altitude.

1. Restart the unit. 40 Measured value invalid.

1. Check that System SW V1.02.05 (or later) is

installed. Update System SW if required.

2. Replace PC 1772 Monitoring.

6 - 14 Service Manual Revision 05

SERVO-i Ventilator System Troubleshooting

Error
code

Error message / Possible cause

42 Checksum failure.

SW checksum failure during startup.

43 Battery information failure.

Battery module status information failure.

44 Alarm limit failure.

Alarm limit settings (with checksum) are
stored. If the checksum is incorrect, this
Technical error alarm is activated.

45 Unexpected shutdown.

Unexpected shutdown. As the unit has
shutdown, this Technical Error is only visible
in the Technical alarm log.

46 Remote alarm failure.

Recommended action

1. Restart the unit.

2. Replace lithium battery on PC 1772 if

together with Error code 29.

3. Replace PC 1772 Monitoring.

1. Replace the Battery module(s).

2. Replace PC 1775 Plug-and-play back-plane.

3. Replace PC 1772 Monitoring.

1. Restart the unit.

2. Replace lithium battery on PC 1772 if

together with Error code 29.

3. Replace PC 1772 Monitoring.

1. Restart the unit.

2. Replace PC 1772 Monitoring.

1. Replace PC 1789 Remote alarm connector.

Remote alarm connector failure or
communication failure with PC 1772.

48 Pre-oxygen time exceeded.

The max. ‘Pre-oxygen time’ during Suction
Support exceeded. The system has not
returned to ventilation using the previous
settings after the ‘Pre-oxygen time’.

49 Disconnect time exceeded.

The max. ‘Disconnect time’ during Suction
Support exceeded. The system has not
returned to ventilation using the previous
settings after the ‘Disconnect time’.

50 Communication failure.

Communication failure between ID PROM on
PC 1770 Main back-plane and Monitoring
subsystem. System ID, configuration,
operating time, etc, not available.

51 On/Off switch failure.

The On/Off switch is neither in On or Off
position during more than 3 seconds.

2. Replace PC 1772 Monitoring.

1. Replace PC 1771 Control.

6

1. Replace PC 1771 Control.

1. Replace PC 1772 Monitoring.

2. Replace PC 1770 Main back-plane.

1. Replace PC 1777 Panel.

Applicable only on units with PC 1772 Rev 18
or later and System SW version V3.02.01 or
later.

52 O

Revision 05 Service Manual 6 - 15

Sensor cannot be used with Heliox. 1. Replace the O

2

Sensor with an O2 cell.

2

Troubleshooting SERVO-i Ventilator System

Error
code

Error message / Possible cause Recommended action

53 PC 1784 Expiratory Channel version conflict. 1. Replace PC 1784 Expiratory Channel.

PC 1784 must be of Revision 16 (or later)
when used with Heliox.

Also note that PC 1785 Expiratory Channel
Connector of Revision 03 (or later) is a
prerequisite for Heliox.

54 System ID conflict.

Conflict during startup between information
stored on PC 1770 Main back-plane and
PC 1772 Monitoring.

1. Restart the unit.

2. Replace lithium battery on PC 1772 if

together with Error code 29.

3. Replace PC 1772 Monitoring.

Breathing

1. Replace battery on PC 1771 Control. 10001 Lithium battery depleted

The lithium battery on PC 1771 Control is
depleted.

6

Communication failure with ID PROM on
PC 1771 Control.

10003 Ventilation stopped

Error in the internal memory detected.

This technical alarm is common after a SW
installation. Restart the unit and check that no
technical alarms are activated.

If TE10003 remains, this indicates a HW error.

1. Replace PC 1771 Control. 10002 Communication failure

1. Restart the unit.

2. Replace PC 1771 Control.

6 - 16 Service Manual Revision 05

SERVO-i Ventilator System Troubleshooting

Panel

1. Replace PC 1777 Panel. 20001 Communication failure

Communication failure with ID PROM on
PC 1777 Panel.

20002 Backlight broken

The backlight power consumption is
measured. If the power consumption is
outside specified range during >20
consecutive readings, this technical error is
activated.

This error message may also be logged
immediately before the ‘No battery capacity’
alarm when the unit is running in battery
mode.

20003 Button stuck

Membrane buttons are checked during
startup. If any button is detected as pressed,
this technical error is activated.

If the display is lit (and the error code is shown
on the display):

1. Replace PC 1777 Panel.

If the display is not lit (the display is dark):

1. Replace backlight lamps.

2. Replace PC board Backlight Inverter.

Note 1: If one of the lamps is broken, the other
lamp will automatically be switched off.
Thus, with a failure on a backlight lamp, or likely
also on PC board Backlight Inverter, the User
Interface display will become dark. This error
code will in such case not be possible to see
(but will be logged).

Note 2: If the User Interface is placed too close
to the MR scanner, the PC board Backlight
Inverter may become defective.

1. Restart the unit. Do not touch the User

Interface during system startup. Interfering
with the knobs, keys, touch screen,
loudspeaker grid, etc, may affect the internal
technical tests.

6

20004 Alarm sound level too low

The loudspeaker is checked using a
microphone during startup:

• On PC 1777A-C; one beep (silent before

and after).

• On PC 1777D or later; three beeps (silent

between).

20005 Checksum failure

SW checksum failure during startup

2. Check that System SW V1.03.00 (or later) is

installed. Update System SW if required.

3. Check the user interface membrane buttons

(FSS).

4. Replace the touch screen.

5. Replace PC 1777 Panel.

1. Restart the unit. Do not touch the User

Interface during system startup. Interfering
with the knobs, keys, touch screen,
loudspeaker grid, etc, may affect the internal
technical tests.

2. Check that System SW V1.03.00 (or later) is

installed. Update System SW if required.

3. Replace the loudspeaker.

4. Replace PC 1777 Panel.

1. Replace PC 1772 Monitoring.

Revision 05 Service Manual 6 - 17

Troubleshooting SERVO-i Ventilator System

Expiratory Flow Meter

40001 Exp. flow meter failure

See information logged together with error
code 40001 in the Service log / Technical
alarms.

Technical alarm ‘Expiration flow meter PC 1784’
and ‘Exp. cassette EEPROM read/write error’:

1. Replace PC 1784 Expiratory channel.

Technical alarm ‘Expiration flow meter PC 1784’
and ‘Exp. cassette EEPROM checksum error’:

1. Replace PC 1784 Expiratory channel.

Technical alarm ‘Expiration flow meter PC 1784’
and ‘PC 1784 thermistor failure’:

1. Replace Expiratory cassette.

Technical alarm ‘Expiration flow meter PC 1784’
and ‘PC 1784 60 V overrange’:

1. Replace PC 1778 DC/DC & Standard

Connectors.

Technical alarm ‘Expiration flow meter PC 1784’
and ‘PC 1784 60 V underrange’:

1. Replace PC 1771 Control.

6

2. Replace PC 1778 DC/DC & Standard

Connectors.

6 - 18 Service Manual Revision 05

SERVO-i Ventilator System Troubleshooting

Other Technical error alarms

Error message / Possible cause Recommended action

Restart ventilator

Communication error between PC 1777 Panel
and PC 1772 Monitoring.

Technical error in Expiratory cassette

Technical error in Expiratory cassette or in the
communication with the cassette.

CO2 module error

Hardware error in the CO

Analyzer module.

2

1. Restart the ventilator and perform a Pre-use check.

2. Check the Control cable that connects the Patient

Unit with the User Interface.

3. Replace PC 1778 DC/DC & Standard connectors.

4. Replace PC 1772 Monitoring.

5. Replace PC 1777 Panel.

1. Replace the expiratory cassette.

2. Replace PC 1785 Expiratory channel connector.

3. Replace PC 1784 Expiratory channel.

If the Service log / Technical alarms ‘Expiration flow
meter Exp. cassette power failure’ is logged together with
error code ‘Technical error in Expiratory cassette’:

1. Replace PC 1771 Control.

2. Replace PC 1778 DC/DC & Standard Connectors.

1. Unplug and reinsert the module.

2. Replace the module. There are no spare parts

available for the CO
malfunction, the module must be replaced.

Analyzer module. In case of

2

CO2 sensor error

Hardware error in CO
The values in the capnostat memory failed the
internal test.

Nebulizer hardware error

Technical problem with nebulizer hardware.

Temperature in the nebulizer patient unit too
high.

Technical problem with connection cable.

Edi Module error

Hardware error in the Edi Module.

Y Sensor Module error

Hardware error in the Y Sensor measuring
module.

capnostat sensor.

2

1. Unplug and reinsert the capnostat sensor.

2. Calibrate the capnostat sensor.

3. Replace the capnostat sensor. There are no spare

parts available for the capnostat sensor. In case of
malfunction, the sensor must be replaced.

1. Check buffer liquid level.

2. Restart the nebulizer.

3. Replace the nebulizer patient unit.

4. Replace connection cable.

5. Check internal connection cable

6. Replace PC 1771 Control

1. Unplug and re-insert the Edi Module.

2. Replace the Edi Module. There are no spare parts

available for the Edi Module. In case of malfunction,
the module must be replaced.

1. Unplug and reinsert the module

2. Replace the module. There are no spare parts

available for the Y Sensor Module. In case of
malfunction, the module must be replaced.

6

Revision 05 Service Manual 6 - 19

Troubleshooting SERVO-i Ventilator System

Notes

6

6 - 20 Service Manual Revision 05

6 - 4 Service Manual Revision 05

SERVO-i Ventilator System Preventive maintenance

Only personnel trained and authorized
by MAQUET shall be permitted to
perform installation, service or
maintenance of the SERVO-i.

Make sure to prepare the SERVO-i properly
before disassembling and assembling. Refer to
section 'Hazard notices' in chapter 'Important'.

Any service or maintenance must be noted in a
log book.

After any installation, maintenance or service
intervention in the SERVO-i, perform a 'Pre-use
check'. Refer to the 'SERVO-i Ventilator System –
User's Manual' for details.

This product contains electronic and
electrical components. Discard
disposable, replaced and left-over parts
in accordance with appropriate industrial
and environmental standards.

7. Preventive maintenance

General.............................................................. 7 - 2

Preparations...................................................... 7 - 2

Equipment ......................................................... 7 - 2

Preventive Maintenance calculation

and notification ................................................. 7 - 2

Preventive maintenance ................................... 7 - 3

Maintenance kit, 5,000 hours ........................ 7 - 3

Performing the Preventive maintenance ....... 7 - 3

Revision 05 Service Manual 7 - 1

7

Preventive maintenance SERVO-i Ventilator System

General

• A 'Preventive maintenance' must be performed at
least once every year as long as the unit is not
used more than normal. Normal operation is
estimated to correspond to approx. 5,000 hours of
operation. Also refer to section 'Preventive
maintenance calculation and notification' below.

• The life span for the Battery module is calculated
to two and a half year from manufacturing date.
Normal time for logistics and storage are included
in this calculation. The calculation corresponds
thus to an estimated operational time of two years.
Manufacturing date (year-week) is printed on the
battery label.

• The internal Lithium batteries on PC 1771 and
PC 1772 shall be replaced every five years.

• It is recommended that a regular cleaning and an
extended cleaning of the inspiratory channel
should be performed before carrying out
'Preventive maintenance'. Refer to instructions in
the User's Manual.

• In some parts of the Preventive maintenance, as
described in this chapter, access to the Field
Service System (FSS) is required.

• Some optional equipment used with the SERVO-i,
but not covered by this Service Manual, may also
demand maintenance actions. Refer to the optional
equipments documentation. Example on such
optional equipment are:

– Humidifier
– Compressor Mini.

Preparations

• Make sure that the SERVO-i works properly before

7

performing any maintenance.

• Check if there are any unexpected 'Technical
alarms' in the 'Service log' available via the
'Biomed menu'. 'Technical alarms' are available
also via the Field Service System (FSS).

• Set the On/Off switch on the User Interface to Off.

• Disconnect the mains power cable.

• Disconnect the gas supplies (wall and/or cylinder).

• Remove patient tubing.

• If fitted, remove bacteria filter from the expiratory
inlet.

Equipment

• Standard service tools.

• Barometer (or information about the actual
barometric pressure).

• Access to the Field Service System (FSS).
Recommended but not required.

• Preventive maintenance-kit containing all parts
needed during the maintenance.

Preventive Maintenance calculation and notification

As from System version 4.0, the calculation of time
until next Preventive Maintenance has been
changed. Furthermore, a Preventive Maintenance
notification has been introduced.

Calculation

The calculation of time until next preventive
maintenance (5,000 hours) has been changed. It
includes only operating hours, standby hours are
excluded.

Notification

Preventive Maintenance notifications will be shown
on the User Interface. The notifications are shown
after the 'Pre-use check' dialogue (performed or
cancelled).

There are two different time limits for these
notifications:

• The first type of notification will be shown when
there is 200 hours or less until next Preventive
Maintenance.

• The second type of notification will be shown when
there is 0 hours until next Preventive Maintenance,
i.e, time limit for Preventive Maintenance is
exceeded.

These notifications are active by default, but can be
disabled via the Field Service System (FSS).

7 - 2 Service Manual Revision 05

SERVO-i Ventilator System Preventive maintenance

Preventive maintenance

Maintenance kit, 5,000 hours

Only original parts from the manufacturer must be
used. Spare parts and maintenance kits can be
ordered from your local MAQUET representative.

When performing this maintenance, a 'Maintenance
kit, 5,000 hours' should be used.

The following parts shall be replaced and they are
included in the 'Maintenance kit, 5,000 hours':

A. Filters for the gas modules

B. Nozzle units for the gas modules

C. Bacteria filter for the inspiratory pressure

transducer

D. Bacteria filter for the O2 cell

SVX9066

Performing the Preventive maintenance

• Disassembling and assembling of the unit is
required when replacing parts included in the
'Maintenance kit, 5,000 hours'. If not stated
otherwise, refer to chapter 'Disassembling and
assembling' for instructions.

• The letters A – D in the text below refers to the
description of the Maintenance kit above.

• Prepare the unit as described in section
'Preparations' above in this chapter.

Gas modules

A. Replace filters in the gas modules. When

replacing filter, move the rubber seal from the old
to the new filter.

7

SVX9067

Revision 05 Service Manual 7 - 3

Preventive maintenance SERVO-i Ventilator System

B. Replace plastic nozzle units in the gas modules.

After replacement of plastic nozzle units, wait 10
minutes before connecting pressure to the gas
modules.

SVX9068

Inspiratory pressure transducer filter

C. Replace the filter for the inspiratory pressure

transducer. Make sure that the filter is correctly
seated into the rubber ring.

Refer to instructions in the 'SERVO-i Ventilator
System – User's Manual'.

7

Note: This filter may already be replaced as a part of

the 'Extended cleaning of Inspiratory channel'
performed in combination with the Preventive
maintenance.

SVX9069

Bacteria filter for O2 cell

D. Replace the bacteria filter for the O2 cell (if

applicable).

Refer to instructions in the 'SERVO-i Ventilator
System – User's Manual'.

Note: This filter is not used on the O2 Sensor.

SVX9070

7 - 4 Service Manual Revision 05

SERVO-i Ventilator System Preventive maintenance

Internal fan filter

• Remove the internal fan filter (1).

• Check if the filter is damaged. Replace damaged
filter.

• If not damaged, clean the filter. The filter can be
rinsed in water. Shake out and make sure that the
filter is free from excess water.

• Mount the new/cleaned filter.

SVX9071

a

Internal fan

• Connect the mains power cable.

• Set the On/Off switch to Standby.

• Disconnect the O2 Sensor/cell connector (1).
This is done to protect the O2 Sensor/cell during
the Internal fan-test.

• The temperatur sensor controlling the Internal fan
is mounted in the cable connector (1). Carefully
warm-up the cable connector (1) and check that
the Internal fan starts. Use e. g. a light bulb or a
heat fan to warm the connector.

• The Internal fan will start at approx.:

SVX9072

33 °C (91 °F) with half effect

43 °C (109 °F) with full effect.

a

Note 1: The temperature must not exceed
70 °C (158 °F).

• Re-connect the O2 Sensor/cell connector (1) and
mount the inspiratory section cover.

Note 2: If the unit is equipped with an O2 Sensor,
restart to avoid 'O2 cell / sensor failure' alarm.

7

Expiratory cassette

• Remaining operating capacity (in %) for the
membrane can be shown in the 'Status' window.
Select Status / Exp. cassette to check 'Remaining
membrane capacity'.

• When this capacity limit is passed or if the
membrane for some reason has become defective,
it must be replaced. Refer to instructions in
chapter 'Disassembling and assembling'.

• The operating capacity meter must be reset after
replacement of the membrane. To access the reset
button, select Menu / Biomed / Service.

Revision 05 Service Manual 7 - 5

Preventive maintenance SERVO-i Ventilator System

User Interface

• Check the touch screen readability:

– Transparency

– Surface

– Brightness (backlight). Estimated lifetime (with

acceptable brightness level) for the lamps is
30,000 hours. Using the Field Service System
(FSS), a time meter for the lamps can be shown.
The time meter must be reset after replacement
of the lamps.

• Check if pixels on the touch screen are defective.
Open the Status window. A few defective pixels
can be accepted. Check that defective pixels are
not concentrated to a small area thus reducing the
readability in this area.
FSS is recommended but not required.

• Perform the checks listed below and make sure
that the software responds to these actions. FSS is
recommended but not required.

– Check the touch screen functions. Press buttons

on different parts of the touch screen.

– Check the Main Rotary Dial. Turn and press the

Main Rotary Dial.

– Check the Direct Access Knobs. Turn all Direct

Access Knobs.

– Check the membrane buttons. Press all

membrane buttons.

Barometric pressure

• Select Status / General on the User Interface.
Check that the Barometric pressure value shown
on the User Interface corresponds to the actual

7

Barometric pressure value at the local site. The
value shown on the User Interface may not differ
more than ±5% from the actual barometric
pressure.

• If the value shown on the User Interface differs
more than ±5% from the actual barometric
pressure, the barometer in SERVO-i must be
calibrated. FSS is required.

Gas supply pressure transducers

• Connect the gas supplies (Air and O2).

• Select Status / General on the User Interface.

• Disconnect the gas supply, one gas at the time.

• Check that the corresponding supply pressure
value in the 'Status'-window drops.

Battery modules

System SW version V2.01.00 (or higher) includes an
advanced monitoring of the battery status. The
System SW will, among others, monitor:

• Expiry date. The life span for the Battery module is
calculated to two and a half year from
manufacturing date.

• If the operational capacity is too poor for continued
usage.

In both cases, battery replacement information will
be shown on the User Interface.

Select 'Status / Batteries' on the User Interface to
check battery status. For further information, refer to
chapter 'Service procedures', section 'Battery
modules'.

Lithium batteries

• Check manufacturing date for the lithium batteries
mounted onto PC 1771 and PC 1772. The
batteries must be replaced after 5 years.
Replacement is described in chapter 'Service
procedures'.

Safety inspection

• Make a visual inspection of the SERVO-i for
external defects or damages. Replace defective or
damaged parts.

• Check the mains power cable and control cable
and their connections for damage.

On SERVO-i systems approved for use in MR
environment, check that:

– Two ferrite blocks are mounted on the control

cable.

– Two ferrite blocks are mounted on the mains

power cable.

• Perform a leakage current test. The use of an
Electrical Safety Tester is recommended. The
leakage current test is a standard procedure
regulated by IEC/EN 60601-1 or corresponding
national standards. Allowable values and test
methods are defined in the standard:

– SERVO-i Base unit: IEC/EN 60601-1 Class 1,

Type B.

–CO2 Analyzer Module: IEC/EN 60601-1 Class 1,

Type BF.

– Edi Module: IEC/EN 60601-1, Class 1, Type CF.

• Check that a 'SERVO-i Ventilator System – User's
Manual' corresponding to the installed System
version is present. Also check that operating
manuals for all optional equipment connected to
the SERVO-i are present.

7 - 6 Service Manual Revision 05

SERVO-i Ventilator System Preventive maintenance

Completing the Preventive maintenance

• Perform a 'Pre-use check'. Refer to the
'SERVO-i Ventilator System – User's Manual'.

• Perform 'Function checks' on the optional
equipments connected to the SERVO-i. Refer to
the operating manuals for these optional
equipments.

• Reset the Preventive maintenance time meter.
Use the reset button (select Menu / Biomed /
Service / Report PM) or use the FSS. Also note in
the units log book that a Preventive maintenance
has been performed.

Revision 05 Service Manual 7 - 7

7

Preventive maintenance SERVO-i Ventilator System

Notes

7

7 - 8 Service Manual Revision 05

SERVO-i Ventilator System Index

Only personnel trained and authorized
by MAQUET shall be permitted to
perform installation, service or
maintenance of the SERVO-i.

Make sure to prepare the SERVO-i properly
before disassembling and assembling. Refer to
section 'Hazard notices' in chapter 'Important'.

Any service or maintenance must be noted in a
log book.

After any installation, maintenance or service
intervention in the SERVO-i, perform a 'Pre-use
check'. Refer to the 'SERVO-i Ventilator System –
User's Manual' for details.

This product contains electronic and
electrical components. Discard
disposable, replaced and left-over parts
in accordance with appropriate industrial
and environmental standards.

8. Index

Alfabetic index .................................................. 8 - 2

Revision 05 Service Manual 8 - 1

8

Index SERVO-i Ventilator System

A

AC/DC Converter 2-7, 3-10, 4-15

Aeroneb Pro 2-2, 3-12

Aeroneb Solo 2-2, 3-12

Alarm output connector 2-2, 2-6, 3-12, 10-2

Assembling guidelines 4-2

B

Backlight inverter 2-5, 3-3, 4-3, 4-6

Backlight lamp 2-5, 4-3, 4-9

Bacteria filter for O2 cell 7-4

Barometric pressure 7-6

Battery module 1-5, 2-3, 2-6, 3-12, 4-26, 5-2, 7-2,

7-6

Battery module locking device 4-15, 4-26

Biomed key 5-4

Breathing SW 2-9

C

Cable reel 2-4

Change access code 5-5

CO2 Analyzer module 2-3, 2-6, 3-10, 3-12, 6-19, 7-6

Compressor Mini 2-3, 3-12

Connector muff 2-8, 3-4, 4-21

Control cable 2-4, 3-11, 4-26

Control cable connector 2-6, 10-2

D

Direct access controls/knobs 2-4, 2-5

8

Display with touch screen 2-4

ESD protection 1-4, 4-2

Expiratory cassette 2-8, 3-6, 5-7, 6-19, 7-5

Expiratory cassette membrane 3-7, 4-24

Expiratory inlet 2-6, 2-8

Expiratory one-way valve 2-8, 4-25

Expiratory outlet 2-6

Expiratory section 3-6

Expiratory valve 2-8

Expiratory valve coil 2-7, 2-8, 4-23, 5-7

External +12V DC power supply connector 2-6, 10-2

F

Field Service System (FSS) 5-10

Fixed key 2-4

Fixed keys label 4-10

Flash memory 3-2

Front cover 4-14

Functional check 1-5

Functional Main Blocks diagram 10-3

Fuse F1 2-6, 3-10

Fuse F11 2-6, 3-10

Fuse F12 2-6, 3-10

G

Gas cylinder restrainer 2-3, 3-13

Gas inlet 2-6

Gas module 2-8, 3-3, 4-21, 7-3

Gas supply pressure transducer 7-6

Gas trolley 2-3, 3-13

H

E

Handling PC boards 4-2

Edi Module 2-3, 2-6, 3-10, 3-13, 6-19, 7-6

Edi SW 2-9, 2-10, 3-13

Edit configuration 5-5

EEPROM 3-2

Environmental declaration 1-6

Equipotentiality terminal 2-6

8 - 2 Service Manual Revision 05

Hazard notices 1-4

Heating foil 2-8

Heliox 2-3, 2-6, 3-3, 3-5, 3-7, 3-13

Holder 2-3, 3-13

Humidifier 2-3, 3-14

Humidifier holder 2-3, 3-14