Checking the turbo brush of the robot vacuum cleaner Xiaomi

Smart tech owners often face a situation where the device stops sucking up garbage, although it seems to be working visually, and if you notice that the robot vacuum cleaner makes unusual noise or stops pulling dust at all, the problem often lies in the turbo brush assembly, and this element is responsible for knocking the pile out of the carpets and sucking up heavy fractions, so its performance is critical.

Before you disassemble the body and get inside the machine, you need to do a primary diagnostic without tools, often the cause of malfunction is a trivial hair winding on the axle or the stuck large debris that blocks the rotation of the shaft, but if mechanical cleaning did not help, you will have to check the motor and the power chain with deeper methods.

In this article, we will discuss in detail the algorithm of actions that will allow you to determine whether the motor is alive or needs to be changed. We will look at methods of multimeter vertebrating, visual inspection of the collector group and checking the control board, which will help save time on the trip to the service center.

Primary diagnosis and external signs of malfunction

Before you pick up a screwdriver, you should carefully listen to the operation of the device. A proper turbo brush motor emits a characteristic smooth hum of high frequency. If you hear a crackling, grinding or whistling when you start cleaning, this is a sure sign that the shaft bearings have worn out, or a hard object has entered the mechanism that damages the impeller.

Note the indication on the body or in the Mi Home app. Many models, such as the Xiaomi Vacuum Mop 2 Pro or Roborock S5 Max, are able to diagnose engine errors through current sensors. If the app gives an error "Turbo brush blocked" or "Check main brush" even on a clean carpet, this may indicate that the engine cannot gain the necessary speed due to wear or break of the winding.

⚠️ Warning: If you smell burns or see sparks in the area of the brush assembly when turned on, immediately disconnect the device from charging.Operation with a faulty engine may cause fire or damage to the main motherboard.

It's also worth checking the physical condition of the brush. Take off the lid and try to swipe the shaft with your hand. It should rotate with little force, but it's free. If the shaft is jammed dead, don't try to unwind it by force, which can break the plastic gear of the gearbox that connects the motor to the shaft.

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Before diagnosis, always completely discharge the battery or disconnect its plume from the board to avoid short circuit in case of accidental contact of the multimeter probes with other components.

Tools and workplace preparation required

To test a turbo brush properly, you’ll need the minimum set of tools any home builder can find, with precision and accuracy as fasteners in Xiaomi devices are often made of soft metal and easily derailed if handled carelessly.

You will need the following tools:

• 🔧 A set of Phillips screwdrivers (cross) of different sizes, necessarily magnetic, so as not to drop the screws inside the case.
• 🔌 Multimeter (tester) for measuring the resistance of windings and checking the integrity of the chain.
• 🧹 Tweezers with thin curved ends to extract hair and debris from hard-to-reach places.
• 🧴 Spray-cleaner contacts or isopropyl alcohol for degreasing contacts.

Pay special attention to the choice of place for disassembly. The surface should be clean, well-lit and not villous, so that small details do not get lost. It is recommended to use a magnetic mat or organizer for screws, since the design of a robot vacuum cleaner involves the use of many fasteners of different lengths.

If you don't have any experience with electronics, you can have a smartphone with a camera, and take a picture of each stage of the disassembly, especially the location of the plumes and wires, and this will help you put the device back together without errors, because the plugs on the board may look similar but have different wiring.

Dismantling of the turbo brush assembly and engine access

The disassembly process may vary depending on the specific model of your Xiaomi robot vacuum cleaner. In most cases, such as the Roborock S50/S55 series or Xiaomi Vacuum 1S, access to the turbo brush engine is from the bottom of the device, but sometimes a partial removal of the upper casing is required.

First, flip the robot over and remove the main brush. Then unscrew the screws that fix the plastic frame of the turbo knot. Be careful: often under the frame there are additional screws that hold the engine body itself. Once the protective cover is removed, you will see a black cylindrical block, which is the turbo engine that we will be testing.

Disconnect the plume or connector that runs from the engine to the control board. It's usually fixed with a plastic lock that needs to be carefully bent with a nail or a plastic blade. Don't pull the wires, just take the plastic connector. Once the power is turned off, you can remove the engine from the seat by first unscrewing the screws or unplugging the plastic locks.

In some models, such as the Xiaomi Mi Robot Vacuum Mop P, the engine can be integrated into the prefabricated module along with the gearbox, in which case the dismantling requires more care, since the plastic latches of the module can be fragile with time and heat.

Visual inspection and mechanical inspection

Once the engine is removed, the first thing you do is do a thorough visual inspection, look for signs of overheating: blackening of the insulation, melting of the plastic body of the engine, or the characteristic smell of burnt wiring. If the engine body is deformed or has cracks, further operation is impossible and replacement of the unit is required.

Check the engine shaft. It should not have coiled hair, threads or wool that could create additional resistance. Even a thin layer of compressed dust and hair can create a cushion that will interfere with rotation and cause windings to overheat. Clean the shaft and bearings with tweezers and alcohol.

Try to turn the engine shaft with your fingers. When it is in good condition, it should rotate smoothly, without jerking, jamming or extraneous sounds. If you feel a metal crunch or the shaft stops at certain points, this indicates the collapse of the slip bearings or the entry of a solid particle into the motor.

⚠️ Warning: Do not attempt to disassemble the sealed body of the electric motor (metal cylinder). Factory assembly does not provide for repairs inside, and leakage will lead to a quick failure due to dust hitting the collector.

Electrical check by multimeter

The most accurate way to determine the state of the engine winding is to use a multimeter in resistance measurement mode (Ohms).Switch the device to the range of 200 Ohms or 2 kOhms. Connect the probes to the contacts of the engine connector (or to the terminals of the motor itself, if the connector is bitten off).

The normal resistance of the turbo brush collector motor windings is usually between 5 and 50 Ohms, depending on the model and the power. If the multimeter shows one (infinity), then the circuit breaks, the winding burns out or the contact inside has gone away. If the device shows zero or close to zero, there is an interturn circuit.

It's also important to check that there's no closure, and if you put one probe on the metal body of the engine, and if you put the other on the power contacts, the device should not show any conductivity, and if you have resistance between the casing and the contacts, you're insulating, which is dangerous for the main board of the robot.

If you have a lab power supply, you can apply 12-14 volts (standard for most Xiaomi robots) to the engine and check the current consumption. A faulty idling motor consumes about 0.5-1.5 ampere. A sharp jump in current to 3-5 ampere and a stoppage of rotation indicate a short circuit in the anchor.

Diagnostics of management board and contacts

Sometimes the motor itself is in good shape, but the robot doesn't apply any voltage to it, in which case the problem is the control board or the plume, check the integrity of the wires that go from the board to the engine, and often at the exit point of the plastic connector, the wires break down due to constant vibration.

Look at the connector on the board. The contacts should not be oxidized or have any traces of soot. If you see black dots on the contacts, carefully clean them with a blower or cotton swab dipped in alcohol. The oxides create high transient resistance, which causes the motor to not get enough power.

For advanced users, you can ring the circuit board tracks from the motor connector to the control chip or transistor. If the track is in a cliff, you need to solder the lintel (MOSFET), Which can be replaced if you have the skills of SMD-component.

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If the motor is good for resistance, but does not rotate when connected to the robot, the problem in 90% of cases is in the control board or a wire break in the corrugated plume.

Replacement of the turbo engine and assembly of the device

If the diagnostics confirm that the turbo brush motor malfunctions, it must be replaced. You can buy the original motor or a quality analogue at the robotics parts stores. When buying, pay attention to the length of the shaft, the diameter of the body and the location of the mounting holes.

The new engine is installed in reverse disassembly order. Make sure the sealing gum is in place so that dust does not get inside the mechanism. When you connect the plume, make sure it snaps to the characteristic click.

After assembly, test run without the bottom cover (with care) to make sure the rotation is in the right direction and there is no vibration. If everything is working correctly, set all the covers in place and secure with screws.

• ✅ Make sure the brush is set correctly in the direction of rotation (usually indicated by the arrow on the casing).
• ✅ Check that all screws are twisted but not pulled over so as not to damage the plastic.
• ✅ Run a full cleaning to check work under load.

Regular maintenance of the turbo unit will extend the life of your robot vacuum cleaner. Clean the shaft of hair once every 1-2 weeks, and then the engine will last for many years without the need to replace.

Frequently Asked Questions (FAQ)