DIY hammer screwdriver repair

In detail: DIY hammer screwdriver repair from a real master for the site my.housecope.com.

A screwdriver can be safely ranked as a tool that quite often has to be used not only in everyday life, but also for work on construction sites. But, like any complex technical accessory, the product can break. We will consider how to repair a screwdriver on our own in this text.

The equipment in the construction market, where screwdrivers take a separate place, is quite large. Many models have individual criteria, assembly quality and cost. However, most of the models are characterized by basic principles of operation and internal execution.

The basic elements of any screwdriver include:

the presence of an electric motor;
planetary reductor;
adjustable function button "Start";
reverse switch;
effort regulator;
power unit.

The electric motor is powered by a direct current network, structurally represented by a cylindrical shape. Inside is an anchor with brushes and magnets. The peculiarity of the electrical circuit of the motor assumes that the direction of the supply voltage flow will be directed to the brushes. When the supplied polarity changes, the motor reverses.

The planetary gearbox is an important element capable of converting the high-frequency vibrations of the electric motor shaft into the low-frequency revolutions of the chuck shaft. Typically, these parts are manufactured from wear-resistant plastic or metal. Many screwdrivers are equipped with 2 speed gearboxes. Switching to the first speed mode is necessary for working with self-tapping screws, and at the second speed you can drill into wood, plastic base or metal.

Video (click to play).

The "Start" button starts the device. It is able to control the number of revolutions, providing the ability to select the optimal rotation speed for the chuck shaft. Correspondingly, pressing forcefully will power the engine at high rpm, and as the pressing force decreases, the power criterion will weaken.

The reverse switch is required to carry out operations to change the rotational direction of the screwdriver motor. This functionality is convenient to use not only for tightening, but also for unscrewing screws.

Regarding the force regulator, we can say that it determines the speed of tightening the screws. In current models, a 16-step adjustable graduation is provided, which allows you to determine with maximum accuracy and convenience what tightening speed is relevant when working with various materials.

The power supply for the screwdriver is oversized rechargeable batteries, where the power supply voltage (depending on the model device) can vary from 9 to 18V.

If at some point you find that your screwdriver does not turn on, then most likely it has some kind of malfunction. Practical experience shows that the inoperability of a tool can be observed for two reasons:

the breakdown is associated with the electronics of the device;
breakage can be mechanical.

Understanding the objective causes of electrical breakdown, one can note its characteristic signs:

the product stops responding to switching on;
the device has ceased to regulate the speed;
the reverse operation failed.

Mechanical problems with a screwdriver include problems with wear of internal parts, for example, a characteristic ratchet of the mechanism is heard.As a rule, a faulty screwdriver will begin to make characteristic sounds, where, for example, bushings have been worn out or a bearing has collapsed. This often happens on a hummer instrument.

For example, if the tool stops turning on, then initially you need to check the health of the battery. If, when basing the device on charging, the breakdown has not disappeared, then you will have to arm yourself with a multimeter and start scanning the device in search of the root cause. First of all, take a look at the voltage value indicated on the device case and compare it with the measurement readings on the battery. The data should be roughly the same. If the voltage is too low, then most likely the problem is hidden in the charger or battery pack.For example, the charger can be checked using a multimeter, plugging it into the network, and taking measurements at the terminals of the device at idle. It is important that the voltage criterion is slightly higher than the nominal one. In a situation where there is no voltage, then, unambiguously, the culprit of the breakdown is the charging unit. Interskol screwdrivers "suffer" from this rather frequent problem. In general, fixing the defect will require specific knowledge of electronics or a new unit will need to be purchased.If you find a battery problem, for example, with a Makit screwdriver, you can open this block with your own hands, where the supply elements are located. As a result of opening, research of the connecting wires should be carried out and the quality of the soldering should be ensured. If no visible defects are found, then using a scanner, you should measure the voltage in each element. Values should indicate 0.9 - 1V voltage power. If a block with a low voltage indicator is found in a row, then it must be replaced.

When everything is in order with the battery and charging goes without problems, but the tool refuses to be activated, then it will check the serviceability of the device button. To do this, you will have to disassemble the device and at its terminals coming from the button, you should measure the voltage with a multimeter, which comes at the input of the button. It is necessary to carry out the operation with an active battery. If there is a signal, then the battery must be removed and its contacts must be short-circuited using the clamps. On the multimeter, you must switch to Ohm mode. The screwdriver button is clamped all the way and measures the output voltage. If the value of the resistance readings on the device tends to zero, then the button works properly. This means that the problem should be looked for in the brushes or other modules of the electric motor. If a signal break is detected, the button is recommended to be repaired, thereby returning the screwdriver to the working order of the tools.

Quite often, problems with buttons are associated with poor contact at the terminals. You can simply perform the procedure for cleaning the contacts with sandpaper and the problem will be solved. The main thing is to do everything carefully in the process of disassembling and assembling the device, without losing parts.

A broken gearbox is one of the mechanical problems with a screwdriver. Some of the most common problems with the reduction unit include:

physical curvature of the axis of the reduction shaft;
obvious defect of the working surface of the gears;
failure of the shaft support sleeve or original bearing;
breakage of the pin where the satellites are fixed.

To correct these defects, it will be necessary to physically replace the defective parts, therefore, this type of repair should be entrusted to qualified specialists who are able to correctly and accurately diagnose the breakdown and eliminate it.

One of the most "popular" tools of the home craftsman is a screwdriver. But, like any product, it breaks down. What to do in this case? In some types of work, an electric drill can save the situation, but only in some. You can take the tool to a service center and wait for it to be repaired.But this will take time and money, which will have to be paid to repair the instrument. But, as a rule, the third option is also available - the repair of the Makit screwdriver, and the device of the screwdriver is not so complicated.Let's look at the main symptoms of screwdriver malfunctions and how you can fix them at home on your own.Before proceeding directly to the malfunctions of this tool, it would be nice to briefly get acquainted with the device of the screwdriver and the purpose of its main units. Let's start with this. The photo below shows a disassembled screwdriver, on its basis and consider the purpose of the parts.We'll start with the start button. The button has two functions: turning on the power supply circuit of the electric motor and its speed regulator. When the button is pressed all the way, the motor power circuit is closed by the button contacts to a straight line, providing maximum power and number of revolutions. The speed controller is electronic, it consists of a PWM generator located on the board. Depending on the force of pressing the button, the contact located on the button moves along the board. The degree of the generated pulse per key depends on its location along the board, the role of the key is played by a field-effect transistor (in the photo above it is designated as a "rotation speed regulator"). That is, the dependence is as follows: the harder the user presses the button, the higher the value of the pulse on the transistor and the more it opens, thereby increasing the voltage on the electric motor.Motor rotation is reversed by reversing the polarity at the terminals. Reversal of polarity is carried out by means of changeover contacts, which are flipped by the user using the reverse handle.Electric motor. In this tool, as a rule, single-phase DC collector motors are used. They are characterized by reliability, ease of production and maintenance. The design of such a motor is as follows: a body on which magnets, an anchor and brushes are located.Reducer. Its purpose is to convert a large number of revolutions of the motor shaft into significantly lower revolutions of the chuck shaft. There are two types of screwdriver gearboxes: planetary and classic. The latter is very rarely used, so we will pay attention to the planetary type gearbox. The planetary gearbox consists of:

ring gear;

sun gear, which is attached to the shaft of the electric motor;

satellites and a carrier (their number depends on the number of steps, there are two or three steps).

Without going into subtleties, let's consider the principle of operation of such a gearbox. The sun gear is driven by the armature shaft, in turn, its teeth drive the satellites, which transmit the rotation of the carrier. With a two-stage gearbox, the chuck shaft is connected to the second carrier, with a three-stage gearbox - with the third.The force regulator is designed to adjust the force that is applied to the screw. As a rule, 16 adjustment positions are used. Thus, there is a wide range of screw tightening levels, which allows you to work with very fragile materials (drywall, etc.). Its principle of operation is well illustrated in the video below. Image - DIY hammer screwdriver repair

The chuck is attached to the output shaft of the gearbox and has three cams that securely hold the part in the chuck.

Having considered the main elements of the screwdriver, let's move on to possible malfunctions and possible ways to repair the AEG screwdriver. And we'll start with the electrical part. The main signs of a malfunction of the electrical component of the screwdriver are:

the instrument does not turn on;

no reverse mode switching;

there is no adjustment of the number of revolutions.

The instrument does not turn on. The first thing to look out for when repairing a Skil screwdriver is the battery. If we put it on charging, and it did not help, then we arm ourselves with a multimeter and proceed to troubleshooting.To begin with, we measure the voltage on the battery, it should more or less correspond to the one indicated on the battery case. If the voltage is too low, it is necessary to identify the faulty element: a battery or a charger.You can determine the health of the charger with a multimeter, for this we plug it into the network and measure the voltage at idle at the terminals. It should be a couple of volts more from the nominal indicated on the device. If there is no voltage, the charging unit is faulty. For such a repair of the Interskol screwdriver, knowledge of electronics will be required, otherwise it is easier to buy a new one.If there is a problem with the battery, then to repair the Makit screwdriver with your own hands, you need to open the block with the elements. After the unit has been disassembled, it is necessary to carefully examine all the wire connections and check the quality of the soldering, whether any one has come off. If all connections are intact, we take a multimeter and measure the voltage across each element. Each element must have at least 0.9 - 1V voltage. If an element with a lower voltage is found, it must be replaced. The main thing is that the capacity and type of the cell correspond to the rest (i.e. if NiCd, then NiCd is also needed). You can learn more about the repair of batteries from the article: "Do-it-yourself screwdriver battery repair."If the charger and the battery are in good order, and the screwdriver does not turn on, it is necessary to disassemble the screwdriver. Two wires go from the battery terminals to the button, we take a multimeter and measure the voltage at the input of the button (the battery is inserted in this case). If there is voltage at the input, then we take out the battery and with the help of the crocodile clips we short-circuit the wires from the battery. We put the device to measure resistance in ohms. Press the button all the way and measure at the exit from the button. The device should show the value of resistance tending to zero, if it is - the button is working properly, the problem is either in the brushes or in other elements of the electric motor. If the tester shows an open circuit, the button needs to be replaced or repaired. You can try to repair it yourself, as it often happens that there is no contact at the terminals due to burning, it will be enough to clean it with sandpaper and assemble it. The main thing when parsing a button is not to rush and act carefully, otherwise all the parts will fly apart, and you will have to puzzle for more than one hour how to assemble it.Similar actions will need to be taken in the absence of reverse. We put one probe of the device on the input wire of the button, the second on the contact of the electric motor or the output of the button, this is more convenient. We switch the reverse handle. If everything is working properly, the device will fix a certain amount of resistance, if it is “silent”, the conductivity of the reverse contacts is broken. The procedure for disassembling and cleaning the contacts is the same as described above, as when repairing the Caliber screwdriver.Is the engine running at maximum rpm and there is no rpm control? The cause of the malfunction can be both in the button itself and in the regulating transistor.If all circuits to the electric motor are in good order, but the tool does not work, the malfunction may be associated with the brushes. Ideally, brushes should be changed when they are long, worn 40% of their original length. If the brushes are worn, replace them with new ones; if the brushes are in order, the problem is with the rest of the motor elements. To check the electric motor, you must disconnect the wires that go from the button. After disconnecting the wires, using a multimeter, we measure the resistance value at the wires fastening contacts. If the resistance value is small and tends to zero, most likely a winding break has occurred, either rewinding or a new motor is needed. Image - DIY hammer screwdriver repair

You can check the integrity of the armature windings, since the armature can be bought and changed on your own. To check the armature, it is necessary to measure the resistance on two adjacent collector plates, along the entire circumference.In this case, the normal value is "0". If during the check you find two adjacent plates, with a value other than zero, the anchor needs repair or replacement.

Signs of a malfunction of the mechanical part of the screwdriver may be the following:

during operation, the instrument emits extraneous sounds that were not previously observed;

strong vibration of the tool and chuck breakage;

the screwdriver turns on, but its further work is impossible due to jamming.

The reasons for "extraneous" sounds during the operation of the tool may be the wear of the bushings or the armature bearing. To do this, it is necessary to disassemble the electric motor and examine it for bearing integrity and the degree of bushing wear. The anchor should rotate easily, without friction and distortion. If necessary, these items can be purchased at the store and replaced by yourself.

The most common gearbox malfunctions are:

bending of the gearbox shaft;
wear of the working surface of the gears;
wear of the bearing and / or bearing sleeve of the gearbox shaft;
break in the pin on which the satellite is attached.

In all cases, it is necessary to replace defective gearbox parts. All described actions require attention and sequence in disassembling and assembling the screwdriver. Having shown these qualities, you can independently repair the Interskol screwdriver with your own hands, or any other, and only in some cases resort to the help of a service center.

A screwdriver is a tool often used in the professional field during repair and construction work, as well as in everyday life. Like any electromechanical device, screwdrivers are prone to malfunction. This device is not a complex device, and in the event of a malfunction, the repair of the basic malfunctions of the screwdriver can be done by hand.Below is a figure showing the internal structure of the battery device.In screwdrivers, both collector electric motors and brushless motors (do not have electric brushes) can be installed.If your screwdriver breaks down, then the malfunctions of this unit may be as follows.All faults, except for the electrical plug, can be eliminated only after disassembling the device.To disassemble the device, follow these steps:

disconnect the battery pack from the body of the device;

unscrew all the fasteners holding the 2 halves of the device together;

remove the upper part of the case;

remove all contents from the body of the device;

carefully disconnect the start button from the case without damaging the wires connecting it to the engine;

remove the speed switch;

disconnect the motor, gearbox, coupling and cartridge by unscrewing 4 screws;

To unscrew the cartridge, you need unscrew the screw, which can be seen inside the mechanism when the cams are open. Unscrew the screw clockwise as it has a left-hand thread. After that, the chuck must be unscrewed from the gearbox shaft by turning it to the left (right-hand thread).If you have a battery pack, the first step is to check the batteries in the battery pack by disassembling it. There are collapsible and non-collapsible blocks. In the second case, you will need to carefully insert a screwdriver into the place where the block walls are glued and, slowly, separate them.Further, it is necessary measure voltage on all "banks". The voltage rating is indicated on the case of each battery. The voltage should be slightly lower than indicated, but the same on serviceable batteries. Defective batteries will differ significantly from the rest in terms of voltage output - they will need to be replaced. New batteries can be purchased online.It is important to solder them correctly, that is, in series: the plus of one battery is connected to the minus of the other, and the plus of the second with the minus of the next, etc.If you are the owner network screwdriver, then the verification algorithm is somewhat different. First, you need to unscrew the body of the device and remove one half of it.Take the tester and ring the power cord for an open. In the case of a working cord, you need to check the start button. With the button pressed, check if there is a circuit on its output contacts. If the button is faulty, it will need to be replaced or repaired. How to do this will be discussed later. With a working button, the problem may lie in the electric brushes or the motor.Below is the electrical diagram of the cordless screwdriver.It can be seen from the diagram that 2 wires from the battery are suitable for the button, and 2 wires go out of it to the engine. Also, 3 wires are connected to the button from the transistor, which is responsible for adjusting the speed. To understand the structure of the screwdriver button, it must be disassembled. All wires going to this part do not need to be unsoldered. They will not interfere with disassembly.Take off push mechanism (red) from its seat. Do this with gentle rotational movements, while simultaneously pulling the part in the direction opposite to the button, being careful not to break the jokes.Next, remove button cover... In the places indicated by the arrows in the figure, using a knife and a screwdriver, it is necessary to pry and push out the latches, and then remove the cover.Removing the cover, you will see reverse compartment... But the button mechanism will still be unavailable. Using a soldering iron, separate the 2 elements (indicated by an arrow in the next figure).Carefully pull out the element numbered 1, then remove the cover that covers the compartment with the device turning on mechanism.Holding the return spring, remove the mechanism from the case.In the faulty button, you will see the erased pads.Contact pads wear out quickly due to the poor quality of the metal. Fine metal dust from worn out contacts accumulates between them and closes the pads. As a result of this, a spontaneous start of the apparatus occurs.Remove metal dust using cotton wool dipped in alcohol. If this fails, you can scrape it off with a knife. After these actions, the spontaneous start of the device will stop.If the speed regulator does not work, then the transistor has burned out, which must be replaced.To check the condition of the brushes, you must disassemble engine, bending back the "antennae" located at the end of the body.Then, with light blows of a hammer on the motor shaft, knock the rotor out of the housing.In this case, first, the cover is removed, in which the electric brushes are located.The next photo shows that the collector has black color... This means that it will get dirty with dust from the brushes. As a result of contamination of the collector, as well as the grooves between its plates, the engine power decreases and the brushes spark. It is necessary to wipe the collector with cotton wool soaked in alcohol and clean the grooves with a needle.The following photo shows what a clean manifold looks like.If the brushes are worn out, they will need to be replaced. Some models of screwdrivers are difficult to find on sale original brushes... But you can find brushes that are suitable in size, then trim them on a grinder and connect (solder) to the brush holders.Sometimes, in order to replace the brushes, you will need to saw a groove in them. It depends on how you attach them.To better understand how the brushes are replaced, you can use the following video.The engine brake is a device that stops the rotation of the armature at the moment the start button is released. In screwdrivers, this function is implemented by closing the plus and minus of the motor when the button is released. As a result, a large self-induction occurs, and there is spindle lock (with a lot of sparking from under the brushes). If the engine braking does not work, then it will be necessary to replace the regulating transistor or start button.Mechanical failures of the screwdriver include malfunctions of the ratchet, gearbox and chuck of the apparatus.If the ratchet does not work on the screwdriver, then you will need to disconnect it from the gearbox for troubleshooting. Sometimes special rods are installed in the coupling, which regulate the force, and in some devices, instead of rods, 2 balls are installed in each hole. They are pressed by a spring, which, when the adjusting ring is twisted, presses on the balls.In most cases, repairing a screwdriver ratchet consists in cleaning its components from dirt and applying new grease.If unusual noises are heard in the gearbox, or the spindle rotates in jerks, with slipping, then the failure of the gears of the mechanism, the worn-out teeth on its body, may be the cause.Gears most often break if they are made of plastic (used in cheap machines). If this happens, then they must be replaced.In the next photo you can see the device of the gearbox.The reason that the spindle does not rotate when the engine is running may be the wear of the plastic teeth inside the gear housing.To restore the mechanism to work, it is necessary to disassemble the gearbox (it is better to photograph the disassembly process) and screw it in place of the worn teeth small bolt, ground down to the required size. The place where you will install the bolt must be screwed. It should be located strictly opposite the plastic tooth located on the inside of the case.Make such markings on the back of the case, opposite the first one.Next, drill holes in the marked places.Screw the bolts of the required length into these holes, having previously grinded off so that they are flush with the other plastic teeth. After adjusting the bolts, you can assemble the gearbox with the required amount of lubricant on the gears. This completes the repair of the screwdriver gearbox.To start repairing this unit, you must first remove the chuck from the screwdriver... For this, a complete disassembly of the screwdriver is not required. How to unscrew the keyless chuck is described above.Frequent chuck malfunctions include incomplete output of one of the cams, as shown in the following photo.The cause of the malfunction may be worn out thread on the nut clamping the cams, or worn teeth on the cams themselves. To verify this, you will need to disassemble the cartridge.Disassembly and repair of the screwdriver chuck is done as follows. It is necessary to hit with a hammer on the part protruding in its center. In order not to deform this part, you can lay a small piece of wood.

The top section will not be enough and further chuck disassembly will be required. To do this, lightly clamp the bolt into the cams and hit it with a hammer.

When the inside of the cartridge falls out, its analysis is complete. You will see nut consisting of 2 halves... Most often, malfunctions in the chuck arise from this part. The thread on it wears out and the cams slip when tightened. Therefore, there is an incorrect centering of the latter.

Also, the thread can be worn on the cams, which, like the nut, must be replaced. But if you do not find the necessary parts to change them, then you will need complete replacement of the cartridge... When assembling the cartridge, the cams must be installed at the same level, in a compressed state, after which a nut consisting of 2 halves is put on, and after that the whole structure is placed in the body. When the malfunction is eliminated, you can assemble the screwdriver.

In practice, finding spare parts for a cartridge is troublesome. It is easier to buy a new chuck, since its price is not so high, within 300 rubles.

The three main reasons that lead to the fact that you have to do the repair of the screwdriver with your own hands are:Diagram of a screwdriver device.Any screwdriver has the following basic elements in its design:

Engine.

Reverse.

Reducer.

Regulator of turns.

The transistor of the speed regulator, which is connected to the radiator.

The repair of the device most often has to be done in connection with the occurrence of various malfunctions that are characteristic of cheap and expensive devices. Among them stand out:When a screwdriver breaks down, the main percentage of malfunctions is the battery.

Broken battery.

Broken button for turning on the device.

Burnt out anchor.

The presence of whistles and various squeaks during operation.

Increased tapping of the clamping chuck.

The impossibility of regulating the speed of the screwdriver.

The reverse of the screwdriver does not switch.

The motor of the machine does not stop turning after the screwdriver is turned off.

The device turns on for a split second, followed by wedging.

Consider the features of eliminating each of the listed malfunctions.In order to make sure that the screwdriver battery is damaged, it must be checked with a multimeter.The battery should be checked first before it can be replaced. The battery should be checked by routine measurement of the voltage level using a multimeter at the terminals of the device. You can also check with any other tester. In this case, there should be a coincidence of the output voltage of the batteries in working condition, if they are charged. The values 12V, 18V, etc. indicated on the battery cases must be strictly observed. If this condition is not met, then the device should be replaced.Possible malfunctions of the screwdriver charger lead to the need to disassemble it, followed by checking using a tester that has already been used. Each battery included in a battery must be subjected to a similar test. After identifying the faulty elements, you should buy special elements of the same type with the same capacity in the store in order to install them in the places of the previous ones, replacing the old ones with new ones.When repairing the power button, you must have special skills and relevant knowledge in the field of electronics. Disassembly of the apparatus should be carried out with the utmost care and care. Otherwise, opening the device may cause certain types of parts to easily fall out of the screwdriver.It is best to first make a sketch of the order of arrangement of different springs, contacts and screws.After you have made sure that the cause of the breakdown is in the battery, then it will be necessary to disassemble it.When the case of the device is opened, the device must be checked for the presence of contacts that have darkened in it. If available, it is necessary to clean them with sandpaper.When the switch has already been repaired, it is possible that the device will not adjust the number of revolutions if the trigger is pressed smoothly. However, the functions of the device are not lost when the trigger is fully pulled. In this case, the fault itself is associated with the adjustment circuit. In this case, a complete replacement of the switch is carried out.If there is no reverse in the device, then it is replaced with a reverse switch, but you can also try to repair it. To this end, repairing the reverse is similar to repairing a switch button. The switch cover is lifted carefully. Then the contacts are checked, cleaned and assembled.If burnt or deformed contacts are found under the cover, the reverse must be replaced. In the version of the button, when the reverse is assembled in its body, that is, inside it, the button changes completely.In the event that, when the button is released, the screwdriver motor continues to work, then the button will have to be changed.When, when the button is released, the motor continues to rotate, which did not happen before, then the button changes completely.The reason for the continued rotation of the button may be its release, which was not observed before. This requires a complete change of the button, or it is necessary to replace the transistor separately.You can check the speed regulator using a multimeter configured for ringing the circuits. The governor circuit is not included in the general circuit acting as a result of the full push of the button. This is where the contact closure begins. Two wires are connected to the electric motor of the screwdriver, the same amount falls on the battery button.The power button is connected to a regulating element or field-effect transistor through 3 wires, which is located outside the screwdriver body. It is necessary to connect the probes in order to dial the lead connected to the electric motor and to the input wire.If possible, the probes are connected not only to the motor wire of the device, but also attached to the reverse input contacts. The device can show whether there is a contact or not. Further, in the same way, all measurements are carried out for the other wire, which is the input. Then you should move the reverse lever to repeat the measurements. If there are no contacts, then these changes affect the button.The cause of the breakdown should also be looked for in the brushes of the screwdriver motor.If all the elements of the device are in good working order, as shown by the operations that were carried out earlier, then it is imperative to check the condition of the engine brushes. This can be done by disconnecting the motor from the button by connecting a multimeter to its wires through the probes.If there is little resistance in the circuit, then this may indicate that the brushes are worn out. In this case, the breakage of the anchor is not excluded, which can occur in rare cases. A winding break can also occur. In this case, a complete replacement of the engine is performed. If only the brushes are worn out, then you can restore the screwdriver motor with your own hands.To restore the motors, for some models of screwdrivers, only the brushes are changed, and the element is not completely disassembled. For repairing other models, the back cover of the engine is separated with brushes from its body part. For this purpose, the flanging of the cover is bent without touching its edges, because they must be returned after the end of the assembly to their original place.Flexible wire brushes are spot welded to attach to the holder. Soldering of wires for new brushes is possible. For this purpose, only refractory solder can be used.Prolonged use of the screwdriver can cause the bearings to wear out or become clogged.Before starting the assembly of the electric motor of the screwdriver using a thin wire, which serves as a clamp, each brush is removed in the brush holder, the cover is installed in its original place. In this case, the brushes release and bend around the body along the edges, which contributes to the best pressing of the back cover.If the screwdriver works for a long time, then this may be accompanied by a process of curvature of the shaft related to the gearbox due to heavy loads and pressing the tool. The chuck, twisting around the shaft, sometimes causes a strong runout during the operation of the device. The support bush or shaft bearing can be severely worn. As a result of damage to the bush or only the bearing, and not the shaft, only replace them.Sometimes it is impossible to start the engine for a certain fraction of a second, that is, it stops abruptly. This may be due to the failure of the gearbox. Often the malfunction occurs due to the breakage of the pin, which serves as an attachment to the satellite. It is possible to replace the carrier or the entire gearbox, which may fail if the gear teeth are worn out.If, after carrying out all the above operations, no malfunctions were found in the device, then it is necessary to check the condition of the armature and the serviceability of the motor brushes. In this case, the engine should be disconnected from the switch button, and then the resistance should be measured by connecting a tester of any kind to the engine wires.If there is no resistance in the circuit at all, then this may indicate that the brushes are worn out. In this case, malfunctions in the motor armature are not excluded, which may be associated with a rupture of the winding. However, these types of problems may be rare.