Knauer K-7400S Operating instructions

Semi-Micro Osmometer K-7400S
Service instructions
Document Number: V6700
Document no. VSM-012

Note: For your own safety, read the instructions and follow the
warnings and safety information on the device and in the instructions.
Keep the instructions for future reference.
Phone: [phone] (9-17h, Central European Time)
Fax: [phone]
E-mail: [e-mail]
Languages: German, English
KNAUER Wissenschaftliche Geräte GmbH
Hegauer Weg 38
14163 Berlin
Germany
Phone: [phone]
Fax: [phone]
Internet: www.knauer.net
E-mail: [e-mail]
Document number: VSM-012
Version number: 2.1
Release date: October 14, 2022
Original edition
This document contains confidential information and may not be
reproduced without written consent of KNAUER Wissenschaftliche
Geräte GmbH.
© KNAUER Wissenschaftliche Geräte GmbH 2022
All rights reserved.
KNAUER Technical
Support:
Publisher:
Version information:
The information in this document is subject
to change without prior notice.
For latest version of the instructions, check our website:
www.knauer.net/en/partner-area/Service-manuals.
Legal information

Semi-Micro Osmometer K-7400S Service instructions , VSM-012
Table of contents
1. Important safety notes ................................................................1
1.1 Definition of personal or material damage ....................................2
1.2 Service request form and decontaminationreport .............................2
1.3 Symbols and Signs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Overview ...........................................................................4
3. Replacement.........................................................................5
3.1 Housing ..................................................................5
3.2 Cooling block .............................................................6
3.3 Fan ......................................................................7
3.4 Display...................................................................7
3.5 Power supply .............................................................9
3.6 Mainboard...............................................................10
3.7 Battery of the mainboard ..................................................10
4. Adjustments ........................................................................11
4.1 Checking the performance of the coolingblock ..............................11
4.2 Calibrating the cooling block ..............................................11
4.3 Inserting the adapter into the coolingcavity .................................13
4.4 Setting the temperature of the cooling cavity.................................14
5. Firmware installation.................................................................15
5.1 Windows serial downloader program .......................................15
5.2 Hyper terminal program ...................................................18
6. Troubleshooting.....................................................................21
6.1 Error messages...........................................................21
7. Tips and Tricks ........................................................................22
7.1 Installation...............................................................22
7.2 General handling .........................................................22
7.3 Calibration...............................................................22
8. Spare Parts .........................................................................23

1
Semi-Micro Osmometer K-7400S Service instructions , VSM-012
1. Important safety notes
Only use the device for applications that fall within the range of the inten-
ded use. Otherwise, the protective and safety equipment of the device
could fail.
The service manual is an addition to the existing user manual; it includes all
work that requires the installation of certain components or the opening of
a device‘s housing.
This service manual is intended for the professional service technician
group as follow:
KNAUER service technicians
Service technicians authorized by KNAUER with a certificate
The following knowledge is required:
Good command of English to be able to use the English-language ser-
vice software and online help.
Participation during an installation of a device or a training by the com-
pany KNAUER or an authorized company.
If you do not belong to one of these professional groups, under no cir-
cumstances perform the work described in this manual. In this case,
contact your superior.
Observe the following:
All safety instructions in the maintenance manual
All safety instructions in the user manual
The environmental, installation, and connection specifications in the
user manual
Only use spare parts, tools and cleaning agents recommended or pre-
scribed by KNAUER.
When working with the device, take measures according to lab regulations
and wear protective clothing:
Safety glasses with side protection
Protective gloves
Lab coat
The warranty seal is a security label which indicates if any opening on
instrument has occurred. Most KNAUER products are sold with the blue
seal on the rear side to confirm that KNAUER was the last who took care of
the instrument. An authorized service technician should order and use the
warranty seal in orange color after opening the instrument (Order. no.
V0602).
Checking inten-
ded use
Who may per-
form repairs?
What has to be
taken into
account?
Safety
equipment
Warranty seal

2 Important safety notes
Semi-Micro Osmometer K-7400S Service instructions , VSM-012
1.1 Definition of personal or material damage
Possible dangers related to the device are distinguished in personal and
material damages in this service manual.
Symbol Meaning
Lethal injuries will occur.
Serious or moderate injuries can
occur.
Minor injuries can occur.
Device defects can occur.
Decontamination
Contamination of devices with toxic, infectious or radioactive substances
pose hazards for all persons during operation, repair, sale, and disposal
of a device.
Life-threatening injuries
Health danger if getting in contact with toxic, infectious or radio-active
substances.
Before disposing of the device or sending it away for repair, you are
required to decontaminate the device in a technically correct manner.
All contaminated devices have to be properly decontaminated by a spe-
cialized company or the operating company before they can be recom-
missioned, repaired, sold, or disposed of. All materials or fluids used for
decontamination have to be collected separately and disposed of pro-
perly.
1.2 Service request form and decontamina-
tionreport
Devices which are shipped without the completed document “Service
request form and decontamination report” will not be repaired. If you
would like to return a device to KNAUER, make sure to enclose the com-
pleted document: www.knauer.net/servicerequest

3 Important safety notes
Semi-Micro Osmometer K-7400S Service instructions , VSM-012
1.3 Symbols and Signs
The following symbols and signs can be found on the device, in the
chromatography software or in the service manual:
Symbol Meaning
Warning signs High voltage hazard!
Electric shock hazard!
Danger caused by potentially toxic sub-
stances!
Electrostatic discharge hazard, damages to
system, device, or components can occur.
General warning sign, moderate to minimal
injuries may occur. Damage to system,
device, or certain components is also possi-
ble.
Leak hazard, damage to device can occur.
Note the maximum weight limit, e.g. 0.5 kg!
CE mark A device or system marked with CE fulfills the
product specific requirements of European
directives. This is confirmed in a Declaration
of Conformity.
Testing seals in Canada and the USA at
nationally recognized testing centers (NRTL).
The certified device or system has success-
fully passed the quality and security tests.
The warranty seal is a security label which
indicates if any opening on instrument has
occurred. Most KNAUER products are sold
with the blue seal on the rear side to confirm
that KNAUER was the last who took care of
the instrument. An authorized service techni-
cian should order and use the warranty seal
in orange color after opening the instrument
(order no. V0602).

4
Semi-Micro Osmometer K-7400S Service instructions , VSM-012
2. Overview
A freezing point osmometer is capable of determining the osmolality of
aqueous solutions. The technique uses the fact that osmotically active
compounds depress the freezing point of a solution compared to pure
solvent. This phenomenon is called freezing point depression and is
independent of the nature, size or shape of particles.
The KNAUER freezing point osmometer is a simple, robust and easy to
maintain instrument with following features:
Automatic measurement process
Sample volume between 50 µL and 150µL (plastic measuring head)
Two or three-point calibration
Executable with EuroOsmo7400 software
Data output via printer
Legend
1 Measuring head
2 LCD Display
3 Keypad
4 RS-232 connector
5 Measuring head connector
6 Fan
7 Power switch
8 Power connector
Note: The glass version of measuring head is discontinued and replaced
by plastic version.

5
Semi-Micro Osmometer K-7400S Service instructions , VSM-012
3. Replacement
3.1 Housing
The device has been switched o.
Screwdriver
Process Figure
1. Unplug the main power and
measuring head cable.
2. Place the measuring head
aside and take care to not
damage thermistor or
stirring wire.
3. Loosen three screws on each
side of device 1and remo-
ve the housing backwards.
To mount the housing, proceed in reverse order.
Device defect
The housing oers protection from electrical voltage which is build
inside the device.
Before putting the device into operation, install the housing
completely.
Prerequisites
Tools
Electric shock
Danger of electric shock from voltage-carrying parts inside the device.
The housing serves as a protective cover against voltages inside the
device.
Switch the device o before opening the device.
Pull the power plug.

6 Replacement
Semi-Micro Osmometer K-7400S Service instructions , VSM-012
3.2 Cooling block
The device has been switched o.
The measuring head cable and power cable have been removed.
The housing has been removed (see chap. 3.1).
Screwdriver
Process Figure
1. Remove all cooling block
cables 1from the main
board.
2. Marking the cables before
unplugging is highly recom-
mended.
3. Loosen two screws 2on
both sides of cooling block
holder.
1. Remove the cooling block
upwards.
To mount the cooling block, proceed in reverse order.
Practical Tip The cooling block has to be adjusted/calibrated after the replacement.
The adjustment procedure will be described later in adjustments sec-
tion.
Prerequisites
Tools

7 Replacement
Semi-Micro Osmometer K-7400S Service instructions , VSM-012
3.3 Fan
The device has been switched o.
The measuring head cable and power cable have been removed.
The housing has been removed (see chap. 3.1).
Screwdriver
Process Figure
1. Disconnect the fan cable 1
from the mainboard.
2. Loosen the 4 outermost
screws of the rear plate and
pull it backward.
3. Loosen two diagonally
screws 2on the fan.
4. Remove the fan.
To mount the fan, proceed in reverse order.
3.4 Display
The measuring head cable and the power cable have been removed.
The housing has been removed (see chap. 3.1).
Screwdriver
Process Figure
1. Unplug the grey display
cable 1from the main-
board.
2. By unscrewing the screws
holding the display (see next
figure), remove it backwards.
Prerequisites
Tools
Prerequisites
Tools