Licenciado

Servo ventilator 900 C/D/e
Service Manual

Contents
Contents
Introduction . . . . . . . . . . . . . . . . . .
Principle diagram. . . . . . . . . . . . . . . .

4
6

Pneumatic unit
Gas flow through the ventilator .
Gas supply . . . . . . . . .
Bellows and spring assembly. .
Gas supply unit . . . . . . .
O2cell . . . . . . . . . . .
Relief/safety valve and working
pressuremanometer . . . . .
Flow transducer . . . . . . .
Pressure transducer . . . . .
Inspiratory valve and step motor
Expiratory valve and pull magnet
Non-return valve . . . . . . .
Transducer interface . . . . . .

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19
2023
28
33
39
41
42

Electronic unit
Principle of operation . . .
Reference level generation .
Regulation of inspiration. .
Timing . . . . . . . . .
Monitoring . . . . . . .
Regulation of expiration . .
Voltage supply . . . . .
Input/output . . . . . .

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Disassembling
Disassembling the pneumatic unit . .
Disassembling theelectronic unit. . .
Replacement of step motor assembly
and pull magnet . . . . . . . . .
Replacement of power supply unit .
Replacement of safety catches . . .
Replacement of flow transducer . .

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45
45
45
46

Adjustment of meters Z1 and Z2 . . .
Adjustment of valve arm. . . . .. .
Replacement and adjustment of R5 . .
Removing the front panel knobs . . .
Front panel potentiometer adjustments.
Troubleshooting . . . . . . . . . . .
Index . . . . . . . . . . . . . . .
Block diagram . . . . . . . . . . . .

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46
46
47
47
48
49
52
56Adjustments

The Servo Ventilator 900 was orginally
manufactured and sold by Siemens. Responsibility
for the product was assumed by MAQUET Critical
Care in 2003. Manufacturing of the product was
discontinued in 2004.
Please note that this Service Manual has only
been re-labeled from Siemens to MAQUET. No
further significant changes are made. Thus,
some information in the Service Manualmay be
outdated.
In case of questions, please contact your local
MAQUET representative

Your local MAQUET representative supplies factory
calibrated and tested plug-in circuit boards as well
as other spare parts indicated in the spare parts
list. When exchanging spare parts, always state
serial number of the apparatus and fault-symptom.

Note that the Operating Manual is anindispensable complement to the Service Manual for
proper servicing.

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.
We recommend using MAQUETauthorized
personnel for all service and repairs and the
use of MAQUET exchange parts or genuine
spare parts. MAQUET will not otherwise assume
responsibility for the materials used, the work
performed or any possible consequences of
same.

About this manual
This Service Manual is intended for Servo Ventilator 900 C,
D and E. When reading the manual, please note:

SV 900 C

SV 900 E...