Question 1

How should the screws of the blades of the YARDFORCE MB 400 lawn mower be tightened?

Accepted Answer

The manual for the YARDFORCE MB 400 specifies that the blade screws must remain well tightened to ensure the safety of the device. However, the documentation does not provide a specific torque value in Newton-meters.

Practical tips for tightening:

Tighten the screws firmly but without forcing - the goal is to ensure a good hold without damaging the plastic casing of the robot
Check that the screws do not move during a slight shake
Regularly check (at least before each significant use) that the screws remain securely in place

Important to note: The manual expressly recommends replacing all worn or damaged blades AND screws simultaneously to maintain the robot's balance and avoid vibrations during mowing.

Question 2

Why does my YARDFORCE MB 400 robotic mower not mow the upper part of my lawn?

Accepted Answer

Your YARDFORCE MB 400 robotic mower cannot access the upper part of your lawn for several reasons. The robot has a maximum slope capacity of 35%: if the upper part exceeds this gradient, the robot simply cannot climb. Measure the slope of your lawn or observe if the robot backs up when trying to ascend this area. If the slope is well below 35%, the problem lies elsewhere.

The boundary wire is often the culprit. Ensure that the perimeter cable completely surrounds the mowing area, including the upper part. The wire must be positioned at at least 1 meter from any obstacle (trees, walls, posts, furniture) and must lie flat on the ground for the robot to properly detect the signals. Check that no section of the wire is damaged, raised, or improperly inserted. If the wire does not delineate the upper area, the robot will not recognize it as a mowing zone.

Obstacles and debris can block access. Regularly inspect the area where the robot operates and remove any stones, branches, cables, or debris that could prevent the robot from moving freely. Clear the access paths to the upper part of your lawn.

Also check the cutting height: if it is set too low and the grass at the top is very dense or tall, the robot may have difficulties or consider the area inaccessible. Adjust the cutting height between 20 and 60 mm to start with a less aggressive cut.

The battery autonomy (28V lithium-ion) can also be a factor. If your lawn is up to 400 m² and the upper part is far from the charging station, the robot may not have enough energy to cover it before returning to charge (60 to 90 minutes of charging). Position the charging station centrally and on flat ground to optimize access to all areas.

Finally, ensure that the robot is not damaged or worn. Inspect the blades, cutting system, and moving parts before each use. If any parts are missing, worn, or damaged, the robot may refuse to operate correctly or access certain areas.

If after these checks the upper part remains unmowed, manually test the robot by placing it directly in that area and starting it. If it refuses to operate even manually, the problem is mechanical and a repair is necessary.

Question 3

How to properly install the charging station of the YARDFORCE MB 400 robotic mower?

Accepted Answer

To properly install the charging station of your YARDFORCE MB 400 robotic mower, follow the steps below:

1. Choose the ideal location

Place the station on flat and clear ground.
Make sure there is enough space around for the robot to maneuver easily.

2. Respect the distance from obstacles

Position the station at least 1 meter away from walls, trees, or other obstacles.
This distance facilitates the robot's return to the station.

3. Orient the station correctly

Orient the front side of the station towards the mowing area.
This allows the robot to find its base more easily.

4. Secure the station to the ground

Use the screws or anchors provided to securely fix the station.
Avoid any movement of the station when the robot returns.

5. Connect the station

Connect the station to a suitable electrical outlet.
Ensure that the power cable is secured and does not pose a risk of tripping or accidents.

6. Check the operation

Check that the indicator lights on the station turn on, indicating that it is ready.
Start a mowing cycle to verify that the robot returns to the station to recharge.

By following these tips, you ensure an optimal installation of the charging station for your YARDFORCE MB 400 robotic mower, thus ensuring efficient and uninterrupted operation.

Question 4

How to properly install the boundary wire for the YARDFORCE MB 400 robotic mower?

Accepted Answer

To properly install the boundary wire for your YARDFORCE MB 400 robotic mower, follow these detailed steps:

1. Preparation of materials

Make sure you have the boundary wire provided with the robot.
Gather the fixing stakes and a tool to dig a small trench if necessary.

2. Defining the mowing area

Clearly define the area to be mowed, avoiding obstacles such as trees, flower beds, or garden furniture.
Plan a path for the robot to access the entire surface.

3. Laying the boundary wire

Start unrolling the wire from the charging station.
Place the wire along the edges of the mowing area, following the desired shape.
Ensure that the wire is taut, without loops or knots.

4. Securing the wire

Use the stakes to hold the wire in place.
Drive the stakes in every 1 to 2 meters approximately to ensure the stability of the wire.
If necessary, bury the wire slightly in a shallow trench to prevent movement.

5. Connecting to the charging station

Connect the ends of the wire to the charging station according to the product instructions.
Ensure that the connections are well secured and protected from moisture.

6. Functionality test

Turn on the charging station and the robot.
Check that the robot correctly follows the boundary wire without leaving the defined area.
In case of problems, check the tension and continuity of the wire.

By following these steps, you ensure an effective and secure installation of the boundary wire for your YARDFORCE MB 400 robotic mower.

Question 5

Can the charging station of the YARDFORCE MB 400 robotic mower be installed on a flowerbed away from the lawn to be mowed?

Accepted Answer

No, it is not recommended to install the charging station of the YARDFORCE MB 400 on a flowerbed. Although technically possible, this location has several disadvantages that compromise the proper functioning of the automatic mowing and charging system. The station should be placed on flat, clear ground, preferably in the heart of the lawn area to be mowed.

The first issue concerns the robot's access to the charging station. The MB 400 must be able to locate and return automatically to the station to recharge once its battery is low. A flowerbed, which by definition is an elevated area or has plantings, creates obstacles that the robot cannot easily overcome. Its sensors and navigation system are optimized for moving on a lawn, not on uneven or damaged ground from the robot's repeated passage.

The second issue is the physical stability of the base. The charging station must be securely fixed on firm, flat ground. A flowerbed, often made up of loose soil, mulch, or planting substrate, does not provide the necessary stability. This instability may slightly shift the station during the robot's support while recharging, which can disrupt the alignment of the charging contacts and create electrical connection problems.

You also risk present on the flowerbed. The robot's regular passages to access the station would trample the plants, reduce the lifespan of flowers or shrubs, and complicate the general maintenance of your garden. This goes against the design of the YARDFORCE MB 400, intended exclusively for autonomous lawn mowing.

Ideal location: Place the station on a flat and stable area of your lawn, preferably in a central or accessible zone. Allow a free space of at least 1 meter around the station so that the robot can reach it without obstacles. Avoid placing it under large trees (risk of damage from lightning) and plug it into an electrical outlet equipped with a residual current circuit breaker of 30 mA maximum. Once properly positioned, secure the station with the provided screws and check that the indicators light up correctly.

Question 6

What should I do if my YARDFORCE MB 400 lawn mower robot displays a 'out of bounds' message while the wire seems to be in good condition?

Accepted Answer

The 'out of bounds' message from the YARDFORCE MB 400 lawn mower robot indicates that the robot detects it is outside the mowing area defined by the perimeter wire. Even if the wire appears to be in good visual condition, several factors can prevent its correct detection. Start by checking each of the following points to resolve the issue.

Checking the perimeter wire: Carefully inspect each segment of the wire along its entire length for cuts, tears, wear, or abrasions. Even a very small break (a few millimeters) or a flattened area can interrupt the electrical signal and make the robot think it is out of bounds. Gently pull on the wire to ensure there are no hidden nicks. Pay particular attention to areas where the wire passes under objects, near metal, or where it may have been stepped on.

Positioning and ground contact: The wire must be laid flat directly on the ground and maintained in continuous contact. Check that it is not twisted, folded, or partially lifted. Weather, animals, or soil compaction can move it. Ensure that the wire is securely fastened every 1 to 2 meters with the provided stakes. A wire that is too loose or suspended will not be detected correctly by the robot's sensors.

Checking electrical connections: Check the connections of the wire to the terminals of the charging station (starting and ending point of the circuit). Ensure that the connectors are fully inserted and that there is no visible corrosion (green or white traces). Corrosion of contacts or poor tightening of screws causes a loss of signal. Unplug and replug the connectors a few times to clean the contacts by friction.

Cleaning the robot's sensors: The perimeter and proximity sensors of the YARDFORCE MB 400 can accumulate dust, dried grass, or dirt that interferes with detection. Regularly clean the base of the robot, especially the sensors located under the chassis and at the front. A damp cloth (not wet) or a soft brush is sufficient. A dirty sensor may misinterpret the wire's signal and generate a false 'out of bounds' alert.

Checking the closed loop: The system works correctly only if the wire forms a complete closed loop. Starting from the charging station, the wire must surround the entire mowing area and return to the same point at the station. Visually check that the wire does not end in the middle of the lawn and that it never crosses another part of itself. An incomplete or crossed loop completely disrupts detection.

Restarting and resetting: After checking, turn off the robot completely for 2 minutes, then turn it back on to reset its sensors and detection system. Move the robot away from the charging station and place it in the center of the mowing area before restarting it. If the 'out of bounds' message persists after all these checks, contact YARDFORCE technical support: an electronic malfunction of the perimeter sensor may require expert diagnosis or part replacement.

Question 7

How to restart the YARDFORCE MB 400 robotic mower after a safety stop?

Accepted Answer

After a safety stop of your YARDFORCE MB 400 robotic mower, the restart procedure depends on the cause of the stop. The MB 400 has a safety system that automatically cuts off the motor when lifted, in case of obstacles, or abnormal vibrations. To restart your robot, you must first identify and correct the issue that triggered the stop.

Step One: Completely stop the robot

Press the STOP button (large red button) to immediately stop the robot
The blades will continue to spin for a few seconds after stopping, even after pressing STOP
Wait at least 5 seconds for the blades to come to a complete stop before any intervention
Set the main power switch to the OFF position, marked by the number 0

Step Two: Diagnose the cause of the stop

Visually inspect the robot and its surrounding area to identify obstacles (branches, stones, wires, debris) that may have blocked it
Remove any obstructions you find, especially in the cutting area and grass ejection
Check that the blades are not damaged or misaligned
Check the battery level: a low battery can trigger a safety stop
If the robot vibrated abnormally, inspect the bolts, screws, and cutting assembly for any damage
Ensure that the safety devices (front bumper, sensors) are not broken

Step Three: Restart the robot

Once the issues are corrected, set the main power switch to ON, marked by the number 1
The robot should emit a sound or light signal confirming activation
Wait a few seconds for the system to reset
Start a new mowing cycle normally

Prevention Tips

Regularly inspect the mowing area and remove obstacles before each use
Keep the blades clean and in good condition; clean the robot after each use
Ensure that the battery is sufficiently charged (at least 50%) before starting a cycle
Check that the power switch is functioning properly and is not damaged
Never use the robot on wet grass, as this increases the risk of blockage

If after these steps the robot still does not restart or stops again shortly after restarting, this may indicate a more serious problem requiring repair. Contact the technical service or an authorized YARDFORCE repair center for a complete diagnosis.

Question 8

How to reactivate the YARDFORCE MB 400 robotic mower after a winter storage period?

Accepted Answer

To reactivate your YARDFORCE MB 400 robotic mower after winter, start by fully charging the battery. According to the manual, the device should be stored with its battery fully charged at room temperature (around 20 °C). If the battery has been kept discharged, connect it to the provided charger and let it charge completely before any use. Important: during winter storage periods, each complete discharge reduces the battery's capacity. It is recommended to recharge the battery approximately every 6 months during prolonged periods of non-use.

Once the battery is charged, perform a complete visual inspection of the robotic mower. Inspect the entire device for any cracks, worn, or damaged parts due to storage. Carefully clean the robotic mower, especially the blades, wheels, and chassis to remove any debris, grass, or dirt accumulated during winter. Check that the blades are securely attached and in good cutting condition. Replace them if they show signs of wear or damage.

Before starting, also inspect the peripheral cable that defines your mowing area and ensure that no obstacles (stones, sticks, wires) obstruct this area. Unplug the charging station from the electrical outlet before setting the main power button to the OFF position if you are handling the robot. Then plug the charging station into an electrical outlet equipped with a residual current circuit breaker (30 mA maximum) in a dry and sheltered location.

Before each use, visually check the condition of all cables, the length, and the type of extension cords used to detect any damage or signs of aging. Also, check that the main power button works correctly and is not damaged. Ensure that all nuts, bolts, and screws remain tight to guarantee the safety of the device during operation.

Perform a startup test by first pressing the STOP button, then manually starting the robot to check that the wheels turn correctly, that the blades operate without abnormal noise, and that the robot can return correctly to its charging station. Never leave the tool operating automatically without supervision during this initial test. Once these checks are successfully completed, you can program your robot to resume its usual mowing cycle based on grass growth in spring.

Important tip: never place heavy objects on the robotic mower or its charging station when they are stored or in operation. If you need to move the robot from one place to another, first press the large STOP button to stop the tool, then ensure that the main power button is in the OFF position before lifting it by the handle located under the tool at the back, keeping the blade support away from your body.

Question 9

Where is the switch on the YARDFORCE MB 400 robotic mower and how do I use it?

Accepted Answer

The switch on the YARDFORCE MB 400 robotic mower is located on the top of the device, usually near the battery compartment. It can be identified by a power symbol, often represented by a circle with a vertical line.

To use the switch:

On: Toggle the switch to the "ON" position to turn on the robotic mower.
Off: Toggle the switch to the "OFF" position to completely stop the device.

Always make sure to turn off the robot before handling or transporting it to ensure your safety.

Question 10

How to resolve the issue of the "mowing time" indicator flashing and the YARDFORCE MB 400 mower robot not starting after winter storage?

Accepted Answer

If the "mowing time" indicator is flashing on your YARDFORCE MB 400 mower robot after winter storage and the robot does not start, this generally indicates a problem related to the battery, configuration, or a temporary malfunction. Here are the steps to follow to resolve this issue:

1. Checking and recharging the battery

Place the robot on its charging station and let it charge for several hours, ideally overnight.
Ensure that the charging contacts are clean and properly aligned.

2. Inspecting the connections

Check that the battery is correctly installed and that the connectors are not corroded or damaged.
Gently clean the contacts if necessary.

3. Resetting the robot

Turn off the robot using the main switch.
Wait about 5 minutes to allow the system to reset.
Turn the robot back on and observe if the indicator stops flashing.

4. Cleaning the sensors

Check that the sensors located under the robot are not obstructed by dirt or debris.
Clean them with a soft, dry cloth.

5. Checking the mowing settings

Check that the programmed settings, including the mowing duration, are correct and suitable for the season.
Modify them if necessary to allow for normal starting.

If after these checks the problem persists, it may be a more technical malfunction requiring specialized assistance.

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