SKF TKST 21 User manual

Instructions for use
SKF TKST 21

2EN
Safety precautions .......................................................................................................................... 3
EU Declaration of Conformity .......................................................................................................... 4
UK Declaration of Conformity .......................................................................................................... 4
1. Instructions for use................................................................................................................... 4
2. Technical data........................................................................................................................... 6
3. Getting started: ........................................................................................................................ 7
4. General usage........................................................................................................................... 7
5. Menus and functions................................................................................................................. 8
5.1 Navigation......................................................................................................................................................8
5.2 Live listening .................................................................................................................................................8
5.3 Recordings.................................................................................................................................................. 10
5.4 SKF sample sounds................................................................................................................................... 11
5.5 Settings ...................................................................................................................................................... 13
6. Troubleshooting...................................................................................................................... 14
7. Spare parts and accessories.................................................................................................... 14
Table of contents
Original instructions

3EN
READ THIS FIRST
Safety precautions
Read this instruction for use fully. Follow all safety
precautions to avoid personal injury or property
damage during equipment operation. SKF cannot
be responsible for damage or injury resulting from
unsafe product use, lack of maintenance or incorrect
equipment operation. In case of any uncertainties as
regards the use of the equipment contact SKF.
This device is used for inspecting moving, rotating
and vibrating objects. It may only be used in
accordance with these instructions. The device must
not be opened. Modifications to the device are not
permitted. The manufacturer shall not be liable for
damage resulting from incorrect use or use contrary
to the intended use. Warranty claims will also be
invalidated in this event.
W A R N I N G :
Risk of injury!
• Moving machinery components should not be
touched with the probe.
• Do not touch moving machinery under any
circumstance.
• The device may not be used in potentially
explosive areas.
• Do not set-up the volume at maximum directly
without knowing what the probe is sensing.
Avoid any shock on the probe.
Warranty void!
• Do not expose the equipment to rough handling
or heavy impacts.
• Always read and follow the operating
instructions.
• Opening the housing of the instrument may
result in hazardous mishandling and voids
warranty.
• Do not expose the equipment to high humidity
or direct contact with water.
• All repair work should be performed by an
SKF repair shop.
Correct disposal!
• =The electronic components in the device
contain environmentally harmful substances.
They must be disposed of in accordance with
the environmental regulations in the country
of use.
N O T E :
• Suitable for use in residential, commercial and
industrial area.
• Not intended for medical use.

4EN
EU Declaration of Conformity
TKST 21
We, SKF MPT, Meidoornkade 14, 3992 AE Houten,
The Netherlands herewith declare under our sole
responsibility that the products described in these
instructions for use, are in accordance with the
conditions of the following Directive(s):
EMC DIRECTIVE 2014/30/EU
and are in conformity with the following standards:
RoHS DIRECTIVE (EU) 2015/863
Houten, The Netherlands, December 2022
Guillaume Dubois
Manager Quality and Compliance
UK Declaration of Conformity
TKST 21
We, SKF MPT, Meidoornkade 14, 3992 AE Houten,
The Netherlands herewith declare under our sole
responsibility that the products described in these
instructions for use, are in accordance with the
conditions of the following Directive(s):
Electromagnetic Compatibility Regulations 2016
(2016 No. 1091) and are in conformity with the
following standards:
The Restriction of the Use of Certain Hazardous
Substances in Electrical and Electronic Equipment
Regulations 2012 (2012 No. 3032)
The person authorised to compile the technical
documentation on behalf of the manufacturer is
SKF (U.K.) Limited, 2 Canada Close, Banbury,
Oxfordshire, OX16 2RT, GBR.
Houten, The Netherlands, December 2022
Guillaume Dubois
Manager Quality and Compliance
1. Instructions for use
These operating instructions are an integral part
of the device. They must be stored in an easily
accessible location and passed on to subsequent
users. Ask your supplier if there is something you do
not understand.
W A R N I N G :
Read the operating instructions thoroughly and
follow the instructions provided.
These operating instructions contain important
information about installing, starting up and
operating the stethoscope. Pay particular attention
to the safety information and warnings to prevent
injuries and product damage.
The manufacturer reserves the right to continue
to develop this device without documenting all
developments. Your supplier will be pleased
to inform you as to whether these operating
instructions are current.
Contents:
• Stethoscope: SKF Stethoscope TKST 21
• 2 batteries AA
(Alkaline, works with rechargeable too)
• Headset and cable
• Two probes, one short and one long
• Case and IFU
Description:
See †fig. 1
A- ON/OFF Button / Menu switching button
B- Batteries compartment:
2 batteries AA must be used
C- Probe connector
D- External jack plug
E- Headset jack plug
E

5EN
B
C
D
A
Fig. 1 – Stethoscope SKF TKST 21
Icon showing
the 4 modes
Icon blinks when battery
is below 25%
Icons to indicate
functions Graphical button indication
General aspect of
the device
4/5.
SKF logo
Menu item title
Area changes according to
selected menu item
Fig. 2 – Wireframe
Menu item title

6EN
1. 2.
3.
4/5.
Fig. 3 – Buttons
1. Direct access button left: volume down
2. Direct access button right: volume up
3. Direct access button center
2. Technical data
Designation TKST 21
Frequency range 30 Hz - 15kHz
Operating temperature -10 to +45°C (14 - 113°F)
Output volume Adjustable in 10 levels
Sounds recording
capability
5 memory slots built-in
Display Color backlit TFT display
Sound volume Up & Down & Mute
Symbol on display Battery low
Maximum recorder output 250 mV
Headset 32 Ohm (with ear defender)
Auto switch off Yes, adjustable
Battery 2 × AA Alkaline (included)
Battery lifetime At least 5 hours (continuous use and full screen brightness)
Probe length 70 and 300 mm (2.8 and 11.8 in)
Weight
- Total weight 1 650 g (3.64 lb)
- Instrument 300 g (0.66 lb)
- Headset 290 g (0.64 lb)
Dimensions handset 230 × 70 × 38 mm (9 × 2.8 × 1.5 in)
Case dimensions 360 ×110 ×260 mm (14.2 × 4.3 × 10.2 in)
Fig. 4 – ON/OFF red button

7EN
3. Getting started:
• Unscrew the battery compartment screw
• Insert the AA batteries respecting the polarity
• Close the lid and tighten the screw.
The device is ready to start listening to a machine
with the chosen contact probe: the short one for
easy to access machinery, and the long one for
spaces with limited access. For this reason, do not
direct it at any moving part of a machinery.
Please follow the steps below when setting up
the device:
• Screw the chosen probe tip to the device and
tighten it gently.
• Plug the cable to the headset outlet, use the
90 degrees angle jack plug side.
• Plug the other end of the cable to the device
and secure the jack plug with the thumb screw.
• Push the ON/OFF button for 2 seconds to turn
the stethoscope ON.
• Direct the device at a running machine.
• Push gently to contact the tip of the probe to
the non-movable machine area of your choice.
• Use the desired volume level by pressing the
direct access buttons 1 or 2 for changing the
volume Down or Up.
4. General usage
The Stethoscope offers a wide range of volume level
to operate it and many different functions. When
simply listening to a machine, by pressing the left
or right button (button 1 and 2), the volume goes
Down or Up.
By pressing one more time on Direct Access button
1 at minimum Volume, it will Mute the Stethoscope.
Use the two probes depending on the ease of access
of the area where you want to listen.
4/5.
Fig. 5 – Volume popup
When the user changes the sound volume a popup
appears and the stethoscope gives an audio indication
of the current sound volume (beep).
The popup disappears after 2 seconds.
The output jack plug on the side is there in order to
plug a recording device (not sold by SKF).

8
5. Menus and functions
SKF Stethoscopes offer many different features that
can be easily accessed from the main screen, from
Live listening, Recordings, SKF sound samples and
Settings.
5.1 Navigation
In order to navigate from one menu to the next one,
press shortly the red ON/OFF button, and it will
toggle through the menus in this sequence:
Live listening --> Recordings --> SKF sound
samples --> Settings --> back to Live listening.
In each different menu, the red ON/OFF button,
when pressed shortly, allows to go BACK to the
previous screen of the Stethoscope.
Direct access buttons 1 and 2 will almost always be
dedicated to increase or decrease the volume, or to
scroll a list of items.
Direct access button 3 will mostly be used to achieve
all functions like recording, pause, playing, selecting.
5.2 Live listening
4/5. Memory slot number
Sound indictor
A recording is started
by pressing the
record button
Volume control
Fig. 6 – Controls and indicators
In the Live listening menu, you can simply listen to
the machine you are pointing at (with contact) and
leave whenever you want. Adjusting the volume by
pressing the left or right button (button 1 and 2):
Up or Down.
4/5.
Fig. 7 – Sound

9
4/5.
Fig. 8 – Loud sound
The limiter icon indicates that the auto gain control is
enabled, in order to protect the user against unwanted
signals of the probe inducing peaks of high volume.
It does not necessarily mean that it is active.
During Live listening, you can also choose to
“record” what you’re listening at, if that’s the case,
press the middle button, the red dot recording icon
will change to a square to show you that you can
stop the recordings at any time. The length of one
recording is limited to 60 seconds: the Stethoscope
will automatically stop when the limit is reached and
go back to Live listening.
4/5.
Dot blinks with
1 sec interval
Fig. 9 – Recording
4/5.
Fig. 10 – Succesful save popup
When the stop recording button is pressed,
the recorded sound is saved and a popup appears
showing the recording ID.
The popup disappears after 3 seconds.
When the stop recording button is pressed or when
the time limit is reached.

10
5.3 Recordings
You can record up to 5 personal sounds on the
Stethoscope, and once full, the instrument is going
to delete the oldest sound in order to replace it with
the newest one.
Use the direct access buttons 1 and 2 in order to
select the sound you want (indicated in blue), from
there, you can listen to it by pressing the direct
access button 3 (Playback).
Fig. 11 – Recordings are shown in a table
Fig. 12 – Playback
The playback screen shows the recording number,
the length of the recording and the elapsed playtime.
The volume limit icon also applies to this screen.
During playback, you can go back to the list of
recordings by shortly pressing the direct access
button 3 (or the ON/OFF Button). With a long press
on direct access button 3, you can switch from
your recorded sounds playback to Live listening
and compare both situations. To switch back to the
recorded sound playback, simply press on the direct
access button 3.

11
5.4 SKF sample sounds
SKF Stethoscopes have built-in sound samples
of bearings with several conditions, for more
information, see here:
https://youtu.be/XYESq6k_ZqM
On all sounds, the same deep groove ball bearing
type is used, DGBB 62309 at 2000RPM and under
a load of 20.000N, for all those sounds:
#1: good undamaged bearing
#2: damaged inner ring
#3: damaged inner ring but not so severe
#4: damaged outer ring, stationary
#5: damaged ball, lower frequency
#6: contamination via ashes in the bearing
#7: pump having some cavitation
#8: sequence of all noises
#9: English
#10: French
#11: German
#12: Spanish
#13: Italian
#14: Swedish
#15: Chinese
SKF.015
SKF.011
SKF.012
SKF.013
SKF.014
Sample sounds are
shown in a table
A scrollbar is used
as visual indication
of more samples
The blue bar shows
the selected sample
sound
Buttons can be used
to navigate and
playback sample
sounds
Fig. 13 – Sample sounds navigation
Amount of sample sounds
The stethoscope includes 15 sample sounds
provided by SKF.
Disabling sample sounds
The sample sound menu can be disabled in the
settings menu.
When disabled, the sample icon in the upper
navigation bar will be coloured a lighter shade
of grey
Fig. 14 – Select sound
Use the direct access buttons 1 and 2 in order to
select the sound you want (indicated in blue), from
there, you can listen to it by pressing the direct
access button 3.

12
Fig. 15 – Sample sound playback
The playback screen shows the sample sound number, the
length of the sample sound and the elapsed playtime.
The volume limit icon also applies to this screen.
Long press on direct access button 3 to toggle
from sound samples to Live listening
LIVE
Fig. 16 – Live listening
During sample sounds Playback, you can go back to
the list of SKF samples by shortly pressing the direct
access button 3 (or the ON/OFF Button).
With a long press on direct access button 3, you can
switch from the SKF sample sound playback to Live
listening and compare both situations.
To switch back to the SKF samples list, simply press
on the direct access button 3.
LIVE blinks
with a 1 sec.
interval

13
5.5 Settings
In order to select what function or setting you have
enabled or not, please access the Settings of the
Stethoscope. Use the direct access buttons 1 and 2
in order to scroll to the desired setting, then press
the direct access button 3 in order to select it and
enter the sub-menu of that specific setting.
Fig. 17 – Settings
The different settings are:
Auto off off - 5 min - 10 min
Display brightness 20 - 40 - 60 - 80 - 100%
Factory reset on - off
SKF sounds on - off
Volume limit on - off
W A R N I N G :
Factory reset needs confirmation with the correct
button! If you press the direct access button 3
accidentally, then it goes back to the setting list and
does not trigger a factory reset.
In order to really confirm a factory reset, you
need to press the direct access button 2 when this
pop-up screen is displayed. This is in order to avoid
unwanted factory reset, which would erase all
personal recordings and reset all settings.
Fig. 18 – Factory settings
Fig. 19 – Factory reset

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6. Troubleshooting
Problem Solution
Display is dirty Use a wet cotton swab to clean the display area and a clean, dry cotton cloth to remove
any water remains.
Do not wash the display with too much water or solvents.
Screen is frozen Remove the batteries and wait for 1 minute before placing them back.
Start the device and check that everything works.
Too short
operating time
Replace batteries with new batteries.
Check if another brand offers better performance.
Do not store the stethoscope in very hot or cold environments.
7. Spare parts and accessories
Designation TKST 21
TKST-PROBES 2 probes set
TKST-HEADS Headset
TKST 11-CB Toolcase with inlay for TKST 11, 21 or 31

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© SKF Group 2023
The contents of this publication are the copyright of the publisher and may not be reproduced (even
extracts) unless prior written permission is granted. Every care has been taken to ensure the accuracy
of the information contained in this publication but no liability can be accepted for any loss or damage
whether direct, indirect or consequential arising out of the use of the information contained herein.
MP5507 EN · 2023/01