DIY screwdriver regulator repair

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

The screwdriver is a mobile tool that makes it easier to work with fasteners and screw connections. Until recently, cordless screwdrivers could only be found in the arsenal of professionals, but with the advent of inexpensive household models on the wide sale, their popularity has increased dramatically.

Unlike an expensive professional tool, budget counterparts have a smaller resource, which is why they often fail.

One of the weakest points of a household screwdriver is the start button and reverse switch. As practice shows, it is they that break most often.

As a rule, it all starts with the fact that the soft start function stops working, then a stronger pull on the "trigger" is required to start the electric motor.

Over time, the tool ceases to respond to any manipulation altogether. Often there is a problem of the opposite nature, when the motor starts to work spontaneously.

In some cases, to eliminate the defect, it is enough to disassemble the tool and clean it, although more often a complete screwdriver button replacement... In both the first and second cases, you can fix the problem yourself. Everything in order.

The screwdriver button is the main control element that performs several functions at once:

Turn on / turn on the instrument;
Switching the direction of rotation;
Smooth engine start;
Speed control.

However, each of the controls built into the button block cannot work correctly by itself. Except for the direction of rotation switch, which is usually a separate function block.

Video (click to play).

In most cases, the body consists of three conventional compartments, in which the working units and mechanisms are located.

In the lower part of the body there is an on / off control unit and an electric motor speed control unit.
In the middle part there is the "trigger" of the smooth start (the deeper you press it, the higher the rotation speed of the cartridge). When pressed, the button slides in a special block along the guides, a variable resistor is responsible for adjusting the speed.
In the upper part there is a reverse button - a switch for the direction of rotation of the cartridge. The direction is reversed by reversing the polarity of the voltage applied to the switch.

This is approximately how all control units of screwdrivers of different brands are arranged. To familiarize yourself with the device of a button of a specific instrument model in more detail, we recommend that you study screwdriver button diagram (it is in the instructions).

To diagnose and repair a screwdriver, you will need the following tools:

As a result of active use of any power tool, dirt inevitably accumulates inside its body.

Once in the control unit, it prevents the full movement of the "trigger" and blocks it.

Therefore, before going to the store for a new block, you should try to clean the old one. The carbon deposits formed on the contacts should also be cleaned with fine sandpaper. If the button is non-separable, the entire unit will have to be replaced.

Diagnostic steps:

We disassemble the tool body. To do this, disconnect the battery, unscrew all the screws (they can be hidden behind decorative overlays that will have to be removed).
We check the serviceability of the electric motor. To do this, disconnect two power wires from the control unit and connect them to the battery contacts (the engine should start working).
We disassemble the screwdriver button. To do this, squeeze the plastic latches and separate the two parts of the button housing.
We make a visual inspection of the state of the button for dirt and damage.
Next, you need to carefully assemble the screwdriver button, install it in place and test.

VIDEO INSTRUCTION

If the cleaning of the control unit did not work, it is necessary to replace the entire button unit.

Disassemble the screwdriver (the process is described above);
Install the new button in place of the old one;
Connect the motor to the button terminals (polarity is not necessary in this case);
Assemble the screwdriver by carefully placing the wires in the case.

It is very important to choose a button for a specific model of a screwdriver, since with all the external similarity and visual correspondence, the part may not fit into the grooves. Typically, new buttons are sold complete with battery terminals and a transistor.

One of the most sought-after tools for home craftsmen is the screwdriver. However, this device sometimes breaks like any other. If this happens, in some cases you can replace this tool with an electric drill. If work cannot be done with an electric drill, you will need to take the screwdriver to a service center in order for specialists to repair the tool. However, this can be time-consuming and costly. Therefore, you can use another option - do it yourself repair the screwdriver.

Screwdrivers are commonly used to assemble furniture both at home and in production.

Before making repair work, you will need to familiarize yourself with the design of this device. In fig. 1 you can see this tool exploded.

Elements that are needed in order to make a screwdriver:

multimeter;
clamps;
sandpaper;
spare parts.

Figure 1. The device of the screwdriver.

The main element is the start button, which performs several functions: switching on the power supply circuit of the electric motor and the speed governor. If you press the button all the way, the motor power circuit will be closed by contacts, as a result of which the maximum power will be provided. The number of revolutions in this case will also be the maximum possible. An electronic regulator is installed in the device, which consists of a PWM generator. This element is located on the board. The contact that is placed on the button will move along the board depending on the pressure on the button. The level of the adjustable impulse per key will depend on the placement of the element. A field-effect transistor is used as a key. The principle of operation will be as follows: the more the master presses the button, the greater the value of the pulse on the transistor and the more it will open and increase the voltage on the electric motor.

The reverse of the rotation of the electric motor will be carried out by changing the polarity at the terminals. This process is carried out using contacts that will be thrown by the master using the reverse handle.

Charger device for cordless screwdriver.

In screwdrivers, in most cases, single-phase continuous current collector motors are installed. They are reliable and easy to manufacture and maintain. An ordinary screwdriver consists of the following elements:

The gear structure will convert the high speed of the electric motor shaft to the low speed of the chuck shaft. Screwdrivers can have planetary or classic gearboxes. The latter are rarely used. Planetary devices consist of the following elements:

ring gear;
sun gear;
satellites;
drove.

The sun gear works by means of the armature shaft, its teeth drive the satellites that rotate the carrier.

A special regulator is used to regulate the forces that will be applied to the screw. Most often, 15 adjustment positions are used.

The main signs of a malfunction in this case will be:

the screwdriver does not turn on;
it is impossible to switch the reverse mode;
it is impossible to adjust the number of revolutions.

Diagram of the gearbox of the cordless screwdriver.

The first step is to check the screwdriver's battery. If the tool was put on charge, but this did not help, then you will need to prepare a multimeter and try to find the malfunction with it. First you need to measure the voltage on the battery. This value should approximately correspond to the one indicated on the case. If there is an underestimated voltage, then it will be necessary to identify the faulty element: a battery or a charging device. To do this, you will need to use a multimeter. This device must be plugged into the network, and then measure the no-load voltage at the terminals. It should be several V more than that indicated on the structure. If there is no voltage, then it will be necessary to repair the charging unit. If there is no knowledge in the field of electronics, then it is recommended to purchase a new one.

If the battery is faulty, then you will need to disassemble the unit, inspect all the places where the wires are fastened and check their quality. If there are no damaged connections, you need to measure the voltage on all elements with a multimeter. The voltage should be 0.9-1 V or more. If there is a part with a lower voltage, then it will need to be replaced. The capacity and type of the element must necessarily correspond to the installed parts.

Diagram of the internal structure of the screwdriver.

If the charger and the rechargeable battery are in good working order, but the screwdriver does not work, then this device should be disassembled. Several wires go from the battery terminals, you need to take a multimeter and measure the voltage at the input of the button. If voltage is present, then you need to remove the battery, use the clamps to short-circuit the wires from the battery. The device should show a resistance value that tends to zero. In this case, the element is OK, the problem lies in the brushes or other parts. If the resistance is different, then the button will need to be replaced. To repair the button, in some cases, it is enough just to clean the contacts on the terminals with sandpaper.

In the same way, you will need to check the reverse element. Repair is carried out by cleaning the contacts.

If the electric motor runs at high speeds, and the speed cannot be adjusted, then the problem may be in the button or transistor that is used for adjustment.

The device of the gears of the screwdriver reducer.

If the chains to the engine are in good order, but the screwdriver does not work, then the problem is in the brushes. If these elements are worn out, they will need to be replaced.

The problem may be directly in the engine. To test the electric motor, you will need to disconnect the wires that are connected to the button. Next, using the same tool, you need to measure the resistance value at the wires fixing contacts. If the value tends to zero, then the winding has broken. In this case, you will need to rewind or install a new motor.

You will need to check the condition of the armature windings, since this element can be purchased and changed by yourself. To check the anchor, it will be necessary to measure the resistance on the adjacent collector plates, along the entire perimeter. The value should tend to zero. If, during the check, plates with a resistance that differs from zero are found, then it will be necessary to repair the armature or replace it.

Mechanical problems can be identified as follows:

In the process of work, the screwdriver makes extraneous sounds that were not there before.
The tool vibrates strongly during operation.
Fight of the chuck for the clamp.
The tool turns on, but it is not possible to use it due to jamming.

If during operation the device emits extraneous sounds, it means that the bushings or the bearing are worn out. To fix this, you will need to disassemble the electric motor, and then check the integrity of the bearing and the level of wear of the sleeve. The anchor should rotate freely, there should not be any friction or distortion. These devices can be bought at a construction supermarket and replaced by yourself.

The most common failures of the gear structure include the following:

shaft malfunction;
abrasion of the working base of the gears;
break of the pin on which the satellite is fixed.

In all cases, it will be necessary to replace the defective gearbox elements. All the above steps must be followed carefully. Disassembly of the screwdriver must be done in a clear sequence, otherwise any of the parts may be lost.Anyone can repair a screwdriver, you just need to correctly identify the faulty element.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, 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 supply 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.

If the engine armature is completely burnt out, then the device engine is completely replaced. If only the engine brushes are worn out, then it is better to repair the device yourself. Before starting repairs, gently open the screwdriver motor housing so as not to damage its edges. All stages of work related to the replacement of brushes are indicated above. It is possible that the armature bushings were worn out due to the magnet, which came off and began to come into contact with the armature. After dropping a drop of special oil on the bushing, turn off the engine to wait until the oil has dispersed in all bushings. However, it still requires replacement over time.

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.

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 source of the screwdriver is the rechargeable batteries of the overall size, where the power supply voltage (depending on the device model) 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 screwdriver regulator 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 screwdriver regulator 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.

Video (click to play).