Launch KWB-421 User manual

V1.00.000
2018-08-18

LAUNCH KWB-421 Wheel Balancer User’s Manual
i
Copyright Information
All rights reserved! No part of this publication may be reproduced and stored in any form (electronic, mechanical,
photocopying, recording or other forms) without obtaining written permission from Shenzhen Launch Tech Co., Ltd.(hereinafter
refers to as LAUNCH). The manual is special written for the use of this machine of LAUNCH, therefore we are not responsible
for any use of this information as applied to other devices.
Neither LAUNCH nor its affiliates shall be liable for damages, losses, costs, or expenses result from: user or third party’s
personal accident, misuse, or abuse of this unit, or unauthorized modifications, repairs, or alterations to this unit, or failure to
strictly comply with LAUNCH operating and maintenance instructions.
LAUNCH shall not be liable for any damages or problems arising from the use of other accessories or parts other than original
LAUNCH products or LAUNCH approved products.
Declaration: Other product names used herein are for identification purposes only and the registered trademark ownership
belongs to original companies.
This equipment is intended for use by technical professionals or maintenance personnel.
Trademark Information
is a registered trademark of LAUNCH TECH. CO., LTD. in China and other countries. All other LAUNCH
trademarks, service marks, domain names, logos, and company names referred to in this manual are property rights of
LAUNCH or its affiliates. In countries where any of the LAUNCH trademarks, service marks, domain names, logos and
company names has not been registered, LAUNCH claims its ownership for them. Other trademarks referred to in this manual
still belong to the original registered company. You may not use any trademark, service mark, domain name, logo, or company
name of LAUNCH or other companies referred to in this manual without prior permission from the owners. You may contact
LAUNCH by visiting its website at http://www.cnlaunch.com, or writing to Launch Industrial Park, North of Wuhe Rd.,
Banxuegang, Longgang, Shenzhen, Guangdong, P. R. China, if you have any questions.
General Notice
Other product names used herein are for identification purposes only and may be trademarks of their respective owners.
LAUNCH disclaims any and all rights in those marks.

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Table of Contents
1. Introduction ............................................................................................................................................................................. 3
1.1 General .......................................................................................................................................................................... 3
1.2 Features ........................................................................................................................................................................ 3
1.3 Technical Data .............................................................................................................................................................. 3
2 Transport and Installation ....................................................................................................................................................... 3
2.1 Haulage and installation of the machine.................................................................................................................... 3
2.2 Recommendations ....................................................................................................................................................... 4
3. Cotrol Panel ............................................................................................................................................................................. 4
4. Operation ................................................................................................................................................................................. 5
4.1 Wheel Mounting ........................................................................................................................................................... 5
4.2 Input the Wheel Data .................................................................................................................................................... 6
4.3 Balance Mode Selection .............................................................................................................................................. 7
4.4 Wheel Balancing .......................................................................................................................................................... 8
5. Maintenance and Repair ......................................................................................................................................................... 9
5.1 Self Calibration ............................................................................................................................................................. 9
5.2 Wheel Balancer Troubleshooting ............................................................................................................................. 11
6 The Wiring Diagram of the Power Board ............................................................................................................................. 13

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1. Introduction
1.1 General
The machine is a compute-based wheel balancer with easy operation, accuracy measuring, complete
functions, security and reliability.
1.2 Features
 imported computer element, first rate electric driving system, long service life
 high intensity plastic shield, strictly in conformity to the national safety operation procedure
 “stop” key is available for stopping the running under emergency
 full automatic dynamic balance and static balance detection function
 with the function of balancing three kinds of aluminium alloy rim
 high balance precision ±1g, short balance term 8s/t
 self-calibration and full automatic failure diagnosis function
1.3 Technical Data
Max. wheel weight 65kg Max tire diameter 650mm
Power supply 220V Noise ＜70dB
Balancing accuracy ±1g Rim width 1.5/18”
Rim diameter 10/15” Balancing cycle 8s
Balancing average speed 180rpm Power consumption 1.1kw
2 Transport and Installation
2.1 Haulage and installation of the machine
 To haulage the balancer, the chassis is the only recommended place to lift. Never lift the machine with
the spindle shaft when installation or operation, otherwise will lead the disrepair damage.
 Install the balancer on the steady and smooth ground. It should keep 500mm distance away from the
wall to maintain good air circulation. There are screw holes on the chassis. Anchor screw could be
used to fix the machine on the ground. Measuring error could be brought due to unstable fixing.

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2.2 Recommendations
 Voltage stabilizing power is recommended to use in the area where have not a stable power supply.
 Before starting to use the balancing machine, carefully read the operating instruction manual. Keep the
manual in a safe place for future reference. Consult the technical person for any misunderstanding.
 Do not uninstall or replace the parts without the instruction of the technical person, otherwise the
regular operation of the machine could be affected.
 Do not clean the machine by compressed air with exceeded pressure.
 Use detergent to clean plastic panels and shelves termly.
 The machine operator should not wear necktie, long hair or loose cloth. She or he should stand at the
side face of the machine and make sure that unauthorized personnel do not approach the machine
during the work cycle.
 The balancing machine should not be used for purposes other-than those described in the instruction
manual.
 All the electrical installation should be operated by professional electrician .
 Make sure that the ground wire has a reliable ground connection, and cut off the power when the
maintenance and repair operation is on.
 Circumstance requirement: Temperature: 0℃－50℃，dry and drafty.
3. Cotrol Panel
I. Digital display, AMOUNT OF UNBALANCE, inside
II. Digital display, AMOUNT OF UNBALANCE, outside
III. Indicator, POSITION OF UNBALANCE, inside
Ⅳ. Indicator, POSITION OF UNBALANCE, outside
Ⅴ. Indicators, correction mode selected

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A. Push buttons, manual DISTANCE input
L. Push buttons, manual WIDTH input
D. Push buttons, manual DIAMETER input
Cycle start push button Push button for reading unbalance<5g(car)
Push button for reading unbalance<50g(trunk)
Emergency stop push button Push button for recalculating /self-calibration
Program selection push button
NOTE: Only use fingers to press the push buttons. Never use the pliers for weight fixing/ removing
or any other pointed objects.
4. Operation
Turn on the main power, the balancer begins the interior self-diagnostic program.
If “－A－ 8.0” is displayed on the display window, the balancer can proceed normally.
4.1 Wheel Mounting
Before wheel balancing, remove the old balance leads and mud, carpolite or metal stuck in somewhere, such
as the gaps in wheel. Make sure that the air pressure of the tyre accord with the standard value and there is
no deformation on the rim locating surface and mounting hole. While balancer running, please do not impact
it to ensure the best testing result.
 location mode for small wheel

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Spindle shaft-----wheel (rim attachment face in by)------cone------quick lock nut
 location mode using purpose made flange
This method is available for the tire with a diameter 650 or 750. You could choose flanges according to the
size of the attachment face (two kinks of flange).
Adapter------flange-----wheel----big cone----- lock nut
Note: the adapter should be suitable for the rim center hole, pay attention to the direction, else
measurement error could be possible.
4.2 Input the Wheel Data
I Input the measurement data “A”
II Input measurement data “L”
On the measure statue, pull out the slide ruler and place
its head on the inside of rim and keep the head touch
with the rim. Till the “A”, (wheel mounting distance)
displayed on screen.
Press “+” key to plus a defined value
Press “-” key to minus a defined value
till equal to the correct measured figure.
Measure the wheel rim width by a caliper and by Press
“+”or”-“key to plus or minus a defined value to change
the displayed figure
till equal to the correct measured figure.

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III Input measurement data “d”
4.3 Balance Mode Selection
As shown in the fig, by adhering or clip-on the lead block at different positions, (profiles), the exact balance
effects can be got.
Press “F” key to enter mode Dynamic balance, mode Static balance, mode ALU-1, mode ALU-2 and mode
ALU-3 in turn. This balancing mode is active automatically when the machine is powered on.
Find the named diameter “d” marked on the tyre.
Press “+”or”-“ key to plus or minus a defined value to
change the displayed figure
till equal to the ”d” figure.
Dynamic balance - This is used in testing dynamic imbalance
when the wheel running and to eliminate the imbalance by
clip-on the lead block at two points that got from the testing.
The two points separate is obtained on the outside and inside
of rim. It is suitable for steel or aluminum alloy wheel rim.
Static balance- The mode should be selected in the case of
static rims or rims on which only one lead block is adhered on
one rim. (e.g. Motorcycle wheel).
ALU-1 : It is suitable for the light alloy wheel rim. Adhere to
these two lead blocks on the shoulders of the wheel rim.

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4.4 Wheel Balancing
Note:
ALU-2 : It is suitable for the light alloy wheel rim. Adhere to the
lead block on the position showed in the fig.
ALU-3: Clip-on the lead block at the inner rim and adhere another on
the outside (as showed in the fig.)
 Press start key to perform the balance test. Eight
seconds later, the balancer brakes and the exact
imbalance value can be analyzed and be displayed.
(For example: outside screen displays 10g. inside
screen displays 40g.)
outer imbalance value
inner imbalance value
 Turn the wheel slowly by hand to locate the balanced
point, make sure that all the balance indicators on the
inner lateral side are light. Clip-on or adhere 40g lead
block on the top point of the wheel rim inside
.
 Turn the wheel slowly by hand to locate the balanced
point, make sure that all the balance indicators on the
outer lateral side are light. Clip-on or adhere 10g lead
block on the top point of the wheel rim outside
.
 Repeat above operation till the display screen
shows , the operation ends and remove the
wheel.

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 For the equipment using single phase power supply, when starting the operation push the wheel by
hand one time to assist starting and prolonging service life.
 Make sure all the inputted measurement data are correct. Press “R” key , the value of “A”,”L”,”D”
could be detected automatically.
 Make sure the selected balance mode is suitable for the outline of wheel rim.
 Make sure the lock nut is tightened.
 Do not strike the spindle shaft when installing or removing the wheel.
 When balancing the rim with a clip-on lead block, use a balancing weight to stick the lead block on the
rim edge. After the balancing ends, strike it close on the ground. Do not strike it on the spindle shaft in
order to avoid the damage of the sensor. To keep the adhered lead block being stuck firmly, before
adhering, you must clean the adhering surface and if it is needed should use the organic solvent or
detergent.
5. Maintenance and Repair
5.1 Self Calibration
The self-calibration operation is finished in the manufacturer’s plant. This operation could be re-do if the
machine services too many years or the spares are charged or there is a big imbalance value. Install a
middle-scale wheel (which has a rim diameter 13 or 14 inch) on the spindle shaft. Input the correct value of
“A”,”L” and “d”.
Note: The wheel chose for self-calibration should be in good condition and the value inputted
should be correct else measure error could be possible.
Use a balanced wheel for self-calibration
Ⅰ. Press “R” key, half of a second later, meanwhile press “START”
key, ‘“CAL”－“CAL”’displays on the control window and all the
indicators light and blink. Withdraw the fingers when all the
indicators put out.
Ⅱ. Press “START” key, the wheel revolves and brakes
automatically, ‘“100”－“ADD”’ displays on the control window.
Move the wheel until all six lights on left side are turned on. Attach
an 100g weight at the highest vertical position (12 o’clock position)
on the inner side of the rim.
III. Press “START” key, the wheel revolves and
brakes automatically, ‘ADD’-‘100’ displays on the control window.
Move the wheel until all six lights on the right side are turned on.
Remove the weight from the inner side of the rim and attach it to
the highest vertical position (12 o’clock position) on the outer side
of the rim.

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Use an unbalanced wheel for self-calibration
Locate the unbalanced point of the wheel rim before the operation begins and clip-on or adhere the 100g
lead block on this position.
Trouble shooting for the self-calibration
Error Description Reasons Solutions
Display “E-rr-8-“ 1.Didn’t clip-on the 100g lead
2.The electric connect wire of the
pressure sensor is broken away
3. Computer board error.
1. Perform calibration with 100g of
standard lead
2.Check the connection and Connect
the electric wire
3. Change a computer board.
The self-calibration
performed by using a wheel has a
too big imbalance value
1.The wheel has a big error value 1.Use a balanced wheel
When the self-calibration ends,
there is too big imbalance value
for the 100g lead block or the
position is not on the positive
down or too many lead blocks
were used
1.The wheel has a big error value
or there are something else on
the wheel
2.Unstable displayed value
1.Change a wheel
2.Replace a new computer board
Contact the professional if above methods do not work.
Ⅳ. Press “START” key, the wheel revolves and brakes
automatically. ‘CAL’-‘END’ displays on the control window. The
calibration is done.
Ⅴ. Locate the unbalanced point of the wheel rim on the outside.
Turn the wheel to make all the indicator light. Make a marker with
chalk at the top position of the tire outer edge.
Ⅵ. Following the procedure described in 5.1 “Ⅰ” and 5.1 “Ⅱ”,
clip-on or adhere the 100g lead block on this marked position.

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5.2 Wheel Balancer Troubleshooting
Error Descriptions Reasons Solutions
Screen no display during
start
1.The switch is wrong
2. External circuit is wrong
1.Change another one
2. Check the electric power circuit
with multi-meter.
Display normal, but
the machine can not
start and with some
noise , Err1 displayed
1.The capacitor of the electric machine
is disabled
2.380V power with no enough phase
1.Change capacitor 20UF/400V
2.Check the power
Err2 displayed
1.The wheel is not installed
2. Install the rim but with no tyre.
3. The adaptor is not tightened.
4. The wheel is not installed correctly or
it is not tightened.
5. The belt is over loose or tight.
1.Install the wheel
2.Install the tyre
3.Tighten the anchor screw
4.Install a suitable adaptor
5.Readjust the belt
Err3 displayed The wheel has a too big imbalance
value Change another wheel or do the self-calibration again.
Err4 displayed
1. If the wheel turned reversely, the
phase wire is wrong connected.
2. If the wheel turned forward, the
sensor is wrong.
1.Adjust the phase
2.Readjust the position or change
another one
Err5 displayed The wheel shield is not put down Put down the shield
Err7 displayed EMS memory data lose Do the self-calibration again
Only display “00-00”,no
values displayed
1.The wire of the sensor is cut off or it
is not well connected
2.EMS memory data lose
1.Connect the wire
2.Refer to the manual, correct the
EMS memory value
The value of variable
range exceeds 5 grams
when the wheel turns.
1.The wheel is not clean or the fitting
surface of the rim center hole is
distorted
2.The sensor is wet or the lock nut is
loose
3. The voltage is lower or the air
pressure of the tyre is low or the
adaptor is not tightened or the cabinet
is not fixed on the ground.
1.Change a wheel
2.Drying it or readjust the sensor
3. Install voltage stabilizer; charge the
tyre; tighten the flange or the adaptor
by a lock nut; fix the cabinet on the
ground.
The value of variable
range reaches tens of
grams when the wheel
turns.
1.The wheel is not clean or the
imbalance value is too big.
2.The sensor is out of action
3.The voltage is lower
1.Change a wheel
2.Check the sensor and the
connection
Check the power or install a voltage
regulator

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Error
Descriptions Reasons Solutions
The electric machine
can stop over ten
seconds after the
“START” key is pressed
and there is a reading
displayed on the
window. But there is no
brake signal.
1. The power board is damaged.
2. There is a disturb.
1. Change a power board.
2. Turn off the machine then reset it.
The balanced value is
unstable. It is very hard
to get the value “00”.
1. The sensor is wet or it is damaged.
2. The program is disordered.
1. Readjust it, drying it and re-do
self-calibration or change a sensor.
2. Re-do self-calibration.
The balancer can not
brake when the value
displayed.
1. The brake system is damaged.
2. There is a disturb. 1.Change a power board. 2.Reset the machine.
There is a difference
value over 10g when the
wheel is removed and
installed.
1. The inner bore of the wheel is not
clear or neat.
2. The adaptor is not well installed.
1.Change a wheel
2. Check the installed surface.
Err8 displayed when
self-calibration is done. See 5.1
Imbalance value
exceeds hundreds of
grams
1. These three EMS memory
parameters are disordered.
2. The error value of the wheel is too
big.
1. Readjust the value to the standard
value in term of the manual.
2.Change a wheel
Contact the professional for the problems could not be resolved by above methods.

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6 The Wiring Diagram of the Power Board
Connected to
transformer

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Warranty
THIS WARRANTY IS EXPRESSLY LIMITED TO PERSONS WHO PURCHASE LAUNCH PRODUCTS
FOR PURPOSES OF RESALE OR USE IN THE ORDINARY COURSE OF THE BUYER’S BUSINESS.
LAUNCH products is warranted against defects in materials and workmanship for one year from date of
delivery to the user. This warranty does not cover any part that has been abused, altered, used for a
purpose other than for which it was intended, or used in a manner inconsistent with instructions regarding
use. The exclusive remedy for any automotive meter found to be defective is repair or replacement, and
LAUNCH shall not be liable for any consequential or incidental damages. Final determination of defects
shall be made by LAUNCH in accordance with procedures established by LAUNCH. No agent, employee,
or representative of LAUNCH has any authority to bind LAUNCH to any affirmation, representation, or
warranty concerning LAUNCH products.
Declaration
The above warranty is able to replace any warranty in other forms.
Order Information
Replaceable and optional parts can be ordered directly from your LAUNCH authorized supplier. Your order
should include the following information:
1. Quantity
2. Part code
3. Item description
Customer Service
If you have any questions on the operation of the unit, please call: 86-755-84528767.
If your unit requires repair service, return it to the manufacturer with a copy of the sales receipt and a note
describing the problem. If the unit is determined to be in warranty, it will be repaired or replaced at no
charge. If the unit is determined to be out of warranty, it will be repaired for a nominal service charge plus
return freight. Send the unit pre-paid to:
Attn: Customer Service Center
Shenzhen Launch Tech. Co., Ltd.
Launch Industrial Park,
North of Wuhe Rd.,
Banxuegang, Longgang,
Shenzhen, Guangdong,
P. R. China, 518129