Download Table of Contents Print this page
Husqvarna Automower 420 Workshop Manual

Husqvarna Automower 420 Workshop Manual

Hide thumbs Also See for Automower 420:
Table of Contents


Workshop manual
Husqvarna Automower


Table of Contents

Summary of Contents for Husqvarna Automower 420

  • Page 1 Workshop manual Husqvarna Automower ® 420/430X/430XH/440/450X/450XH/520/550/550H...
  • Page 2: Table Of Contents

    Contents 1 Introduction 6 Repair instructions 1.1 Document description..........3 6.1 Product overview..........18 1.2 Servicing tools............3 6.2 To mount screws..........20 1.3 Technical data............3 6.3 To remove and install the body......20 6.4 To remove and install the upper chassis .....20 6.5 To remove and install the center console....
  • Page 3: Introduction

    1 Introduction 1.1 Document description The Workshop manual is intended for dealers and service personnel, and is a supplement to the Operator’s Manual. The following system is used in Workshop manual to make it easier to use: italics is a text that is shown on the •...
  • Page 4: Safety

    2 Safety 2.1 Safety definitions 2.3.3 Battery safety Warnings, cautions and notes are used to point out WARNING: Lithium-ion batteries can explode or specially important parts of the manual. cause fire if disassembled, short-circuited, exposed to water, fire, or high temperatures. WARNING: Used if there is a risk of injury or Handle carefully, do not dismantle, open the death for the operator or bystanders if the...
  • Page 5 The low voltage cable must not be shortened, extended or spliced. Do not use a trimmer nearby the low voltage cable. Be careful when trimming edges where the cables are placed. Operate the disabling device before you use or lift the product. 1191 - 001 - Safety - 5...
  • Page 6: Product And Installation

    3 Product and installation 3.1 Main components for installation 3.4 Boundary loop The robotic system involves 4 main components: The strength of the A signal varies depending on the distance. The strength of the signal is high close to the •...
  • Page 7: Guide Loop

    3.5 Guide loop 3.7 Circuit boards and sensors The guide wire, together with the part of the boundary The circuit boards and sensors in the product: loop that comprises the return to the charging station, is called the guide loop. The current in the guide loop always goes from the guide wire to the left in the connection between guide wire and boundary loop.
  • Page 8: To Do A Test Of The Installation

    3.7.4 Collision sensors Note: The mean value will be reset if the product has been turned off for more than 50 hours, if the settings The collision sensors are the sensors that detect when are reset, or if the cutting height is adjusted. the product has run into a fixed object.
  • Page 9: Special Menus 420/430X/430Xh/440/450X/450Xh

    4 Special menus 420/430X/430XH/440/450X/450XH The special menus are only available for the models with display, for models without display refer to Autocheck. 4.1 Tools menu overview Tools History, trip Test Special settings Info History, total Calibrate General Key data Wheel Key data Motors Guide...
  • Page 10: Tools Menu (Expert Mode)

    U.SONIC : The version of the program for the 3. Keep the hatch opened and push the hatch locking • devices. ultrasonic sensors. Info - General - Prod menu shows: Total running : The total hours the product has used •...
  • Page 11 The serial number of the circuit board is not No : the product is upside down. normal position, registered on Husqvarna server. Replace the communication board. The Info - Sensors - Temperature menu has this SIMs : Data is not transmitted. Automower •...
  • Page 12 Wheel motor • Tools - History, total - Search times Cutting motor • History, total - Search times menu has 2 sections: Cut height • Overview : Shows the average, max and min search • Info - Motors - Wheel motor menu shows: time of the last 12 searches.
  • Page 13 3. Increase the power to 100% and check that the Note: The product and the charging station must be speed in each wheel is at least 50 cm/s / 20 paired. in./s. 4. Block each wheel and check that the gearboxes 2.
  • Page 14: Quick Info (Limited Tools Menu)

    Accessories - Normal : Applicable in a work area with a If ultrasonic has been turned off from • Ultrasonic , the product will continuously operate at moderate number of obstacles and/or passages. reduced speed 46 cm/s / 18 in./s. Applicable for most work areas.
  • Page 15: Autocheck Service Tool

    5.2 To connect the product Autocheck 3 is a PC tool developed for the service of the robotic lawn mowers from Husqvarna Group. It is a 1. Remove the service plug. tool for troubleshooting as well as a database of sold products and service history.
  • Page 16: Programming Circuit Boards

    Firmware • 5.3.6 Log book Actions • Log book contains the Fault memory where, for Log book • example, the product's error codes can be found. • Documents Additional Log book functions are continuously implemented. Customers • 5.3.7 Documents 5.3.1 Home When a product is connected to Autocheck, only the When the product is connected to Autocheck an relevant technical documentation for that model is...
  • Page 17 5.4.3 Programming a new main circuit board If the main circuit board is replaced, the new main circuit board must be programmed. The main circuit board includes information about the product’s serial number. Note: A new main circuit board may for safety reasons only be assigned one serial number which is never changed.
  • Page 18: Repair Instructions

    6 Repair instructions This chapter describes how to repair and change spare parts. Refer to the Illustrated parts list (IPL) at the manufacturer's support website. 6.1 Product overview 6.1.1 The body system The body system is structured mechanically around the modules that follow: Note: The body system is different between the models.
  • Page 19 1. Joystick, rear 2. Joystick, front 3. Upper chassis Note: There is a sealing strip between the upper and lower chassis. Always replace the sealing strip when the product is opened. 6.1.4 The lower chassis The lower chassis is structured mechanically around the modules that follow: 1.
  • Page 20: To Mount Screws

    6.2 To mount screws 6. The body is attached to the chassis at 4 positions. At each position, hold the chassis with one hand and It is important to mount the screws correctly. Incorrect remove the front cover with a fast and short pull. mounted screws may harm the product.
  • Page 21 5. Disconnect the power cable/cables (A) from the 9. When you connect the cables make sure to put the main circuit board. cables in the cable holders. To put the cables into position in the upper chassis: CAUTION: Always disconnect the power cable first to prevent current spikes that may To put the cables into position in the lower chassis: harm the circuit boards or the battery.
  • Page 22: To Remove And Install The Center Console

    6.5 To remove and install the center console 6. Carefully lift the center console. To remove and install 1. Remove the body. Refer to 7. Install in opposite sequence. the body on page 20 . 6.6 To replace the top cover 430X/430XH/ To remove and 2.
  • Page 23: To Replace The Rear Bumper

    6.9 To replace the keypad 420/430X/430XH/ 4. Install the new top cover into the clips. 440/450X/450XH 5. Install in opposite sequence. To remove and install 1. Remove the body. Refer to the body on page 20 . 6.7 To replace the rear bumper To remove and 2.
  • Page 24: To Replace The Buzzer

    6.12 To replace the main switch 3. Press the clip underneath the body to release the headlight. To remove and install 1. Remove the body. Refer to the body on page 20 . To remove and 2. Remove the upper chassis. Refer to install the upper chassis on page 20 .
  • Page 25: To Replace The Front Joysticks

    3. Remove the 3 screws that holds the front collision brackets to the chassis. b. Close the hatch and remove the 3 screws that hold the bracket. 4. Remove the 3 screws that holds the bracket to the joystick. c. Lift up and remove the bracket. For 520/550/550H: To remove a.
  • Page 26: To Replace The Rear Joysticks

    8. Make sure that the nut is in position in the joystick. 3. Push the clips and lift up the stop sensor with a flat screwdriver. 9. Install the bracket. 10. Install the bellows and make sure that the bellows seal around the retainer.
  • Page 27: To Replace The Start/Stop Button 520/550/550H

    6.17 To replace the START/STOP button 6. Remove the holders. 520/550/550H This section gives information on how to remove all parts. For service or to replace a spare part, all steps may not be necessary. To remove and install 1. Remove the body. Refer to the body on page 20 .
  • Page 28: The Circuit Boards And Sensors

    6.18 The circuit boards and sensors saves this information in the log book and then transfers it back to the product again when the main circuit board These are the circuits boards in the product: has been replaced. 1. Connect the product to Autocheck before replacing the main circuit board.
  • Page 29 placed in a bag with protection against ESD Note: The communication circuit board contains an e- (electrostatic discharge). SIM. For some markets instead a separate SIM card is used. 8. Install in opposite sequence To remove and install 1. Remove the body. Refer to 9.
  • Page 30 6.18.4 To replace the SIM card, 420/440 only as 3. Push the clips to the ultrasonic sensors and lift them accessory For communication circuit boards that have a separate SIM card and not an e-SIM. ® 1. Deactivate Automower Connect in the display ®...
  • Page 31 separately. The front sensor circuit board must be 3. Disconnect the cable from the lift sensor circuit replaced as a unit. board. To remove and install 1. Remove the body. Refer to the body on page 20 . To remove and 2.
  • Page 32: The Battery System

    4. Push with a flat screwdriver on the clip and pull out 4. Push the clips with a flat screwdriver and pull the the holder. rear collision sensor circuit board down to remove it. 5. Install in opposite sequence. 5. Push the clips with a flat screwdriver to remove the collision circuit board.
  • Page 33 6. Remove the battery holder. 4. Remove all cables from the battery/batteries cable holders. 7. Remove the battery from the battery holder. 8. Install a new original Husqvarna battery/batteries in the battery holder. 9. Install in opposite sequence. 6.19.2 To replace the charging plates If the battery of the product does not recharge this may be because of worn or damaged charging plates.
  • Page 34: The Cutting System

    To replace the contact plates in the charging Refer to 5. Remove the 3 screws that holds the skid plate. station on page 39 . To remove and install 1. Remove the body. Refer to the body on page 20 . 2.
  • Page 35: The Wheel Motors

    3. Disconnect the cable for the cutting height Right and left wheel motors are identical and have the adjustment motor from the cutting height circuit same article number as spare parts. The motors have to board. be replaced if they are faulty. 6.21.1 To replace the front wheel and to add grease to the front wheel bearing This section gives information on how to remove all...
  • Page 36 7. Remove the wheel outside and the wheel tire. 10. Remove the ball bearing, the sealing and the shield. 8. Remove the lock washer from the axle. Note: Add grease between the sealing and the bearing and to the ball bearing. 11.
  • Page 37 3. Remove the wheel. 6. For 520/550/550H remove the 3 screws for the inside cover. 4. For 430X/430XH/450X/450XH remove the wheel 7. Install in opposite sequence. cover. 6.21.3 To replace the wheel motors To remove and install 1. Remove the body. Refer to the body on page 20 .
  • Page 38: Charging Station

    3. Remove the screw (hex key 4). 4. Remove the 2 screws on the front of the charging station. 5. Carefully lift the charging cover forward and upward 4. Pull out and remove the wheel brush holder. from the charging tower. 5.
  • Page 39: To Mount Screws In Plastic

    8. Disconnect the cables to the cable plate. 6.22.3 To replace the contact plates in the charging station 1. Remove the charging tower and charging station To remove and install the charging cap. Refer to station and the charging station cap on page 38 . 2.
  • Page 40: To Mount Thread Plugs

    To ensure the threads in plastic parts are not damaged: 3. Make sure the plug is screwed in completely so that a good seal is obtained. 1. Carefully turn the screw counter-clockwise until it engages the existing threads in the plastic. The screw will fall slightly by itself when the threads are located correctly in relation to the existing threads in the plastic.
  • Page 41 3. Lay the other end of the sealing strip above the first end and then out of the channel. Fasten the sealing strip in the retainer. 1191 - 001 - Repair instructions - 41...
  • Page 42: Service

    7 Service 7.1 Service schedule The table below contains a checklist of points and actions to be taken when servicing the product. Complete service plans can be found in Autocheck. Every Every Action Explanation year 3rd year Remove the body and clean the chassis. Refer to To remove and install the body on page 20 .
  • Page 43: Screw Fasteners

    Every Every Action Explanation year 3rd year Open the chassis and replace the chassis seal- Refer to To replace the sealing strips on page 40 . ing strips. 7.2 Screw fasteners All screws are made from stainless material or rustproofed with zinc plating. Article numbers are found in the spare parts list (IPL).
  • Page 44 Fastener Hardware Tool Tightening torque (Nm) Bearing cover, skid plate Screw gray, 4 x 14 mm Torx 20 Blade motor bracket Screw gray, 4 x 14 mm Torx 20 Cutting height adjustment motor Screw gray, 4 x 14 mm Torx 20 1.0/1.3** Charging station, lid Screw gray, 4 x 14 mm...
  • Page 45: Troubleshooting

    8 Troubleshooting 8.1 Messages The table below contains fault and information messages which can appear in the product. There are references to menus in the product, but Autocheck can also be used in many cases. Note: Refer to the Operator's manual for more information about how to rectify errors. Messages Number Message...
  • Page 46 Messages Number Message Cause Action MOTORS 20/21 Wheel motor blocked, Grass or other object has wrapped Check the drive wheel and remove any right/left around the drive wheel. objects. 22/23 Wheel drive problem, The wheel motor is faulty Check the function of the wheel motors right/left when idling.
  • Page 47 Messages Number Message Cause Action INSTALLATION No loop signal Boundary wire broken. Check the signal given by the LED on Loop sig- the charging station. Refer to nal on page 56 . The boundary wire is not connected to Check that the boundary wire connec- the charging station tors are fitted properly to the charging station.
  • Page 48 Messages Number Message Cause Action INSTALLATION Mower lifted The lift sensor has been activated due Free the product and rectify the reason. to the product getting stuck. To replace One of the lift senor magnets is inver- Check the magnet. Refer to the lift sensor circuit board on page 31 .
  • Page 49 Messages Number Message Cause Action INTERNAL DIAGNOSTICS No message Indicates that no message is stored. Loop sensor problem, The cabling to the sensor circuit board Check the levels for the A signal. Refer Tools - Info - Loop on page 10 . front is faulty or has come loose.
  • Page 50 Messages Number Message Cause Action INTERNAL DIAGNOSTICS Problem with ultrason- The ultrasonic sensors are faulty. Replace the ultrasonic sensors. Refer To replace the ultrasonic sensors 450X/450XH/550/550H on page 30 . The ultrasonic circuit board is faulty. Replace the ultrasonic circuit board. Alarm! Mower shut Alarm has been activated as the prod- Adapt the security level of the product...
  • Page 51 Messages Number Message Cause Action INTERNAL DIAGNOSTICS Electronics problem The parameter for the type of product The parameter can only be entered at is different in the HMI circuit board and the initial programming of the main cir- main circuit board. cuit board.
  • Page 52 Messages Number Message Cause Action CHARGING STATION Charging station An object is obstructing the product. Remove the object. blocked The baseplate is bent. Ensure that the baseplate is placed on level ground. The contact between the charging Put the product in the charging station strips and contact strips may be poor and check that the charging strips and and the product has made a number of...
  • Page 53: Symptoms

    Messages Number Message Cause Action MESSAGES WITHOUT ERROR CODE Secondary Needs manual charg- The product is set to the Put the product in the charging station. area operating mode. This behaviour is normal and no further action is required. Ultrasonic problem (In Electronic problem: Ext board error (5) Check that the ultrasonic sensors with the Tools menu)
  • Page 54 5. Charging 6. Miscellaneous Note: Refer to the Operator's manual for more information about how to rectify errors. 8.2.1 Symptoms during mowing Symptom Cause Action Uneven mowing results The product works too few hours per day. Increase the working hours. Work area too large.
  • Page 55 Symptom Cause Action The product does not react An object or dirt under the STOP button. Remove the object or clean under the when pushing the STOP but- STOP button. Faulty micro switch in the STOP button. Replace the STOP button. Refer to The product does not react replace the lock kit, STOP sensor and when the hatch is closed.
  • Page 56: Loop Signal

    8.2.4 Symptoms during charging Symptom Cause Action Battery test to determine the Both the mowing and charging Low battery capacity. Perform a Auto test on times are shorter than usual battery’s capacity. Refer to page 16 . The product never leaves the The parking mode is activated.
  • Page 57 8.3.1 To troubleshoot the loop signal Blue flashing light A blue flashing light is most likely a break in the Always start by checking the LED in the charging boundary loop. station. This usually provides a good indication of where troubleshooting should begin.
  • Page 58: To Find A Break In The Boundary Loop

    8.4 To find a break in the boundary loop normal operation or in connection with it having recently been in operation. A break in the loop wire is normally due to physical damage to the wire, e.g. using a spade while gardening. Note: The values are approximate and vary between In countries with ground frost, also sharp stones that different products and batteries.
  • Page 59: Transportation, Storage And Disposal

    9 Transportation, storage and disposal 9.1 Transportation • If you keep the charging station indoors, disconnect and remove the power supply and all the connectors The supplied Li-ion batteries obey the Dangerous Goods from the charging station. Put the end of each Legislation requirements.
  • Page 60 ORIGINAL INSTRUCTIONS We reserve the right to make changes without prior notice. Copyright © 2019 Husqvarna AB. All rights reserved. 114 15 13-26 2019-07-08...

Table of Contents