Complete disassembly of the screwdriver. DIY screwdriver repair and causes of malfunction

One of the most popular and demanded tools for DIYers is the screwdriver. Due to its mobility, power and versatility, it can cope with any tasks of drilling holes and installing screws and screws. Despite its obvious advantages, in the event of a malfunction, you can repair the screwdriver yourself or transfer it to specialized centers. For most users, the first option (when studying some of the nuances) will be more acceptable, since it will avoid costs and save time. Before starting troubleshooting and eliminating them, it is necessary to familiarize yourself in detail with the operational documentation, as well as pay attention to the design features of a specific device model.

Almost all screwdriver models on the market have a similar design.

The main components of the screwdriver

• Electric motor... It is an executive and main body that converts electrical energy into rotational energy.
• Planetary gear... Allows you to change the direction of rotation of the tool holder.
• Pulse width controller... It makes it possible to adjust the speed when changing the effort on the power button.
• Cartridge... It is a mechanical assembly for fixing bits, drills and other tools.
• Frame... Made of plastic by injection molding, it serves as a skeleton for the installation of all actuating units of the screwdriver. As an aesthetic addition, a rubberized handle is installed on the body.
• Force regulator (ratchet)... Installed between the planetary gear and the chuck. Limits the tightening torque to prevent the bit from slipping in the screw and, as a result, possible damage to the mounted material. Each number on the ratchet indicates the tightening torque, which increases as the number increases.

The main malfunctions of screwdrivers and their elimination

Diagnostics of malfunctions of a screwdriver

Due to the similarity of the construct of the entire model range, screwdriver breakdowns are typical in most cases.

1. Wear of brushes.
2. Chuck breakage.
3. Power button malfunction.
4. Gearbox jamming.

Replacing the brushes of the screwdriver

One of the reasons why the screwdriver stopped working is the strong wear of the brushes. All electric motors have a collector-brush assembly for transferring energy to the armature windings; as such, special contacts are used. They are made of graphite or coal, which do not create high frictional forces with the metal and, as a result, minimize heating.

Repair of the brush-collector mechanism

If the tool fails, you should not start disassembling the screwdriver, because often the reason for this can be a battery malfunction or its complete discharge. If, when replacing the battery, there were no changes in operation, then the reason probably lies precisely in the wear of the brushes. First you need to measure the resistance between them. With a value of about 0, we can say that the breakdown is not covered by the manifold assembly. But if the readings of the multimeter indicate an open circuit, then gently press the brush holder and turn the cartridge. The invariability of the numbers on the tester certainly shows that the contact has not been restored. Therefore, the screwdriver motor should be repaired, and in particular, the brushes should be replaced.

Maintenance-free screwdriver motor

On a traditional serviced motor, everything is extremely simple: we remove the worn-out set of brushes and install a new one. With maintenance-free models, it is a little more difficult, since to disassemble them, gently bend the rolled holders with pliers. After dismantling the cover using a powerful soldering iron, solder and paste, it is necessary to irradiate the three necessary points. Next, having previously cut the wiring, we remove the old brushes and solder the new ones.

Screwdriver chuck repair

Despite the great variety of models, almost all of them are equipped with conventional keyless chucks. For repairs, you will need a small set of locksmith tools. Dismantling this assembly begins by unscrewing the left-hand center screw that secures the chuck to the drive shaft. Next, switch the button for changing the direction of rotation of the shaft and remove the assembly from the cone with a strong jerk counterclockwise.

Screwdriver chuck repair

Due to the fact that the screwdriver chuck is a rather complex mechanism with a mass of small parts, its repair with the replacement of individual parts is problematic due to the lack of free repair kits. Therefore, at home, you can dismantle and install a new cartridge, and it is best to entrust the repair of the screwdriver cartridge to the specialists of the service center.

Repair of the power button

In most cases, finding a suitable power button for a screwdriver is not so easy, since you need to place an order at a service center and wait an indefinite amount of time. Therefore, for many users, a do-it-yourself screwdriver repair will be an excellent solution. First of all, we disassemble the tool and dismantle the pressure mechanism.

Repair of the power button

As a rule, on most models, the power button is red or orange, but this depends on the specific manufacturer. Next, remove the protective case with a knife or flat screwdriver. Carefully, moving in a circle, release the plastic latches and release the reverse mechanism. At the next stage, we release the inclusion element by means of a soldering iron. We warm up the soldering points and separate the case into two parts.

Holding the spring, we remove the switching mechanism and inspect the contact pads, which are subjected to abrasive influences during operation. In most cases, the reason for their wear is the poor quality of the metal. Often this is the reason for the failure of the push-button mechanism.

You can fix this problem by cleaning these areas with sandpaper and cotton wool. After restoring the properties of the contacts, we assemble the power button of the screwdriver in the reverse order of disassembly.

Dismantling and repair of the gearbox

One of the most critical units of a screwdriver is a gearbox, which significantly increases the torque of the output end of the motor shaft. By design, it belongs to a planetary gear train, consisting of a gear, a carrier and satellites. In household models, satellites are made of plastic and, as a rule, are not able to withstand prolonged loads. In professional screwdrivers, these parts are made from high-quality alloy steel.

The motor transmits the rotational motion of the first stage through the sun gear, which is a kind of housing for the entire gearbox. The first carrier drives the second stage of the satellites to rotate. Thanks to such a complex design, the torque is increased tenfold.

With prolonged operation, gears and satellites wear out, therefore, repair of the screwdriver gearbox is required. To begin with, we disassemble the unit and carry out troubleshooting of parts. We carry out the work in the following sequence:

1. According to the instructions described above, we dismantle the cartridge.
2. Using a screwdriver, we unscrew the screwdriver body.
3. Disconnect the gearbox from the electric motor using a screwdriver.
4. We remove the protective plates.

The main parts of the screwdriver gearbox

And so, if the curvature of the shaft is noticeable, then it is better to replace it. Often the cause of jamming or the appearance of extraneous sounds is the broken off top of one of the teeth. Cleaning the parts can correct this problem.

In case of severe wear of the support sleeve and the appearance of play in the bearing, these parts must be replaced with new ones. Broken pinion or pinion gear is a more serious problem and will result in the entire assembly being replaced.

It is worth noting that it is quite difficult to repair the planetary gearbox of a screwdriver at home. Failure of even one part entails the need for qualified repairs, and most importantly, the availability of suitable spare parts.

DIY screwdriver repair: basic aspects was last modified: October 28th, 2018 by Administrator

The 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.

The main malfunctions of screwdrivers and their causes + (Video)

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.

How to repair a screwdriver with your own hands? + (Video)

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.

How to repair a button on a device? + (Video)

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.

https://youtu.be/aZgaQ9OGJJQ

How to repair a screwdriver gearbox? + (Video)

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.

There are unpleasant situations when, in the midst of work, an electrical tool breaks, for example, a screwdriver. There is no time to go to a workshop or a supermarket to buy a new one, which means that it remains to repair it yourself. We will consider below how to disassemble a screwdriver for repair.

• How does it work
• • How the cartridge is attached
  • Dismantle the cartridge
• • Disassembly

How does it work

Cordless screwdrivers are in great use, so we will consider them. The screwdriver resembles a pistol in its appearance. The housing, made of plastic, has holes through which the motor is cooled. If you look at a screwdriver in section, you will see:

• speed regulator;
• reverse;
• a transistor of the speed regulator connected to the radiator;
• electric motor;
• reducer.

How to disassemble the screwdriver as a whole

Consider this process using the Makit screwdriver as an example:

• disconnect the case where the battery is located;
• unscrew the screws connecting the 2 halves of the case with a Phillips screwdriver;
• we extract what is in the screwdriver body;
• dismantle the reverse button;
• remove the speed switch;
• we disconnect the engine and gearbox.

Disassembly is complete.

We disassemble the screwdriver battery

Almost 2/3 of the cost of a screwdriver comes from the battery. Therefore, many people prefer to buy a new tool over repair. But it so happens that a person is used to working with this particular screwdriver and does not want to change it. Then you have to disassemble the battery pack. It's easy to make:

• if the case is collapsible, then just unscrew the fasteners;
• in the case of a CIP case, remove the adhesive layer, push apart the mating surfaces using a self-tapping screw;
• we separate the battery banks. The screwdriver battery has been disassembled.

This video shows another disassembly method:

How to disassemble a screwdriver chuck

The chuck is among the most mobile and loaded units of the screwdriver. Naturally, it wears out more often than other parts.

How the cartridge is attached

Before disassembling the Makita screwdriver, for example, we will determine the method of fastening the chuck. This assembly is attached to the tool by the following methods:

Determine how the manufacturer secured the cartridge

Without knowing how the cartridge is secured, we will not be able to disassemble it. So:

• if the inscription is in the form of 1-6 B10, then there is a Morse cone in the design of the cartridge. At the same time, it is able to clamp shanks with a diameter of 1 to 6 mm, and the tapered surface has a standard size B 10;
• when the method of fixing the cartridge is the thread, then in the case of metric, it is marked with 1.0-11 M12x1.25, and the inch thread is indicated by the marking 2-13 mm? -20 UNF. As a rule, our manufacturers use metric threads, while foreign ones use inch threads.

Dismantle the cartridge

If the fastening of the cartridge is conical, then it can be removed simply - by careful blows with a hammer on the body. When the fastening is threaded, the following actions are performed:

• put the screwdriver on the table;
• run it;
• see if the chuck has moved from its place when the hexagon hit the table surface.

It happens that these actions do not lead to anything, then you will have to disassemble the screwdriver, and then:

• remove the gearbox, and with it the spindle;
• place the knot in a vice;
• take the pipe wrench and unscrew the chuck.

If debris gets into the gearbox, this is the only way to do it. Here is a diagram that will help you understand how to disassemble a Bosch screwdriver:

Here you can see that in a Bosch screwdriver, the chuck and the gearbox are a single unit.

Details on how to disassemble the screwdriver gearbox

Before answering the question of how to disassemble a Hitachi, Zubr, Bosch or any other screwdriver, it does not hurt to know their design.

Planetary gearbox design

The gearbox includes the following parts and assemblies in its design:

• gears - ring and sun;
• satellites;
• drove.

They can be plastic or metal.

Working principle of a 2-stage gearbox

The reducer works like this:

The 3-speed reducer works the same way, but 1 more planetary gear is added there.

Disassembly

The sequence is as follows:

• remove the cartridge;
• untwist the case;
• disconnect the gearbox from the engine;
• remove the plate;
• take out all the details in order;
• we unscrew the bolts connecting the 2 halves of the gearbox;
• adjust the diameter of the spring to the smaller side using pliers. This will improve the inclusion of 1st gear;
• disassemble the coupling by removing the retaining ring, washers and bulk bearing;
• take out the shaft.

To the question of how to disassemble a screwdriver, a video filmed by a master of his craft will be very useful. It will answer general questions and, in particular, how to disassemble the Interskol battery:

But in this video, the disassembly of the Hitachi battery is considered, but using what we saw, we will know how to disassemble the Zubr screwdriver, because they are arranged approximately the same.

Please note: Manufacturers do not produce repair kits for gearboxes. Therefore, all you can do after disassembly is to clean it and change the lubricant. If the parts are worn out, then the repair consists in a complete replacement of this unit. Excessive grease in the gearbox does not contribute to the good performance of the screwdriver.

And in conclusion: in order for the screwdriver to serve properly and do not have to be disassembled often, adhere to simple rules:

• before work, check how the battery is charged;
• choose the right attachments. Landmark - the size of a self-tapping screw or screw;
• after changing the nozzle, fix the cartridge correctly;
• adjust the bit speed before working.

One of the most used repair tools. It can be used to tighten screws for installing wall panels, decorating a room with wood, drilling holes and even stirring mortars and performing other “exotic operations”. Therefore, the breakdown of the screwdriver is a minimum of great annoyance. You can take this device to the workshop. And if it is urgently needed? And there are often breakdowns, which can be eliminated on their own, saving on payment for repair services. In this article, we will look at how to fix a screwdriver with your own hands.

How a screwdriver works

Before repairing any device, you need to know how it works, the logic of its operation, the interaction of units and parts with each other.

The basic design diagrams for all screwdrivers differ little from each other. This device consists of:

1. The case in which all the other nodes of the device are installed. This part is made of metal or plastic, etc. There are models that use these two materials at the same time.
2. Single-phase collector motor with electronic control system - direction of rotation and speed adjustment, selection of operating mode - tightening, unscrewing screws, drilling. The motor consists of a collector and a stator. The collector is powered by spring-loaded copper or graphite brushes.
3. Planetary gearbox with torque limiting capability. The reducer is mounted on the motor shaft. Depending on the model of the screwdriver, this unit is made of plastic or metal. The second option is typical for professional performance.
4. A chuck installed on the output shaft of the gearbox.

Electrical problems

Signs of an electrical malfunction of the device are:

• When you press the start button, the device does not turn on or the rotation of the chuck is slow.
• The instrument works, but sparks and clicks are heard.
• Strong heating of the case is observed even after short-term operation.
• There is no adjustment - speed, direction of rotation, operating mode.

Consider what malfunctions can cause the symptoms described above. The tool does not start and the chuck rotates slowly for the following reasons:

1. The battery is discharged or not charging.
2. An open in the electrical circuit between the battery and the collector motor.
3. Motor malfunction.

If the battery is discharged, it must be charged or replaced with a charged one from the kit - in many models of screwdrivers, 2 batteries are included in the kit.

The reasons why the screwdriver does not charge can be:

• Damage to the charger.
• Battery malfunction.

A breakdown of the charger is detected by measuring the voltage at the output from the device and comparing it with the passport data. Voltages are usually 10.8, 12, 14.4, or 18 volts. The most common batteries are 18V. Moreover, the value of the measured voltage in the case of a working memory device should be slightly higher than the passport one. If the voltage is less or absent, then the charger must be repaired or replaced. You can repair this device yourself, but you need to understand electronics.

If everything is in order with the charger, the battery is to blame. It will either not give out voltage, or give out less than the nominal value. For example, a battery has a nominal voltage of 18 V and outputs 10-11 volts. In this case, a slow rotation of the cartridge will be observed. It should be noted that slow rotation is also caused by mechanical failure. But in this case, the work of the screwdriver will be accompanied by a characteristic noise.

You can also guess that this particular unit has failed by heating it. Why the screwdriver battery is heating up is easy to explain - either poor electrical contact between it and the engine, or poor electrical contact inside this unit, between the battery banks.

How to reanimate a screwdriver battery? In the first case, you need to try to degrease and clean the contacts. In the second, disassemble the battery, if the design allows you to re-solder the contacts. This option is within the power of only a person who has experience in such work. A defective battery can explain why the screwdriver discharges quickly. He either does not gain the passport capacity when charging, or most of it goes into heat due to poor contacts.

In the first case, the battery must be unconditionally replaced. In the second, you can try to clean or re-solder the contacts. True, statistics show that often, even in the case of a successful battery recovery, it is not enough for a long time and, in the end, it is replaced.

An open circuit between the battery and the engine is an air gap between the contacts of these devices. This usually happens in the event of a malfunction of the start button. The malfunction is eliminated by disassembling it, revising the parts - cleaning and rinsing them in a solvent - alcohol or white spirit and cleaning with sanding paper. If the start button also regulates the number of revolutions, as in the model, then knowledge of electronics is required to repair it.

One of the reasons why the screwdriver does not turn is a malfunction of the electric motor. It is subject to disassembly and inspection. First, assess the condition of the brushes. A very common cause of a malfunction is the wear of elements in contact with the collector or the weakening of the spring that presses them. If so, the brushes are replaced. If everything is in order with them, the collector and stator are visually inspected to detect a winding break, and the resistance of its winding is measured with a multimeter. If there is an open circuit, an interturn short circuit or a short circuit to the case, the winding must be rewound. This is done on special equipment and definitely not at home.

Now about why the screwdriver sparks. Sparks occur where the brushes come in contact with the collector plates, especially on high power models, etc.

Perhaps the sparking will be accompanied by a characteristic crackling sound. This phenomenon occurs in 2 cases:

1. Due to poor contact due to wear on the brushes.
2. Slow rotation of the collector due to high mechanical load - drilling into concrete with great effort, etc.

In the first case, the brushes must be replaced. Secondly, to treat the screwdriver more carefully.

Strong heating of the case is caused by:

• heating the battery;
• heating at the point of contact between the battery and the electric motor;
• sparking at the point of contact between the brushes and the collector;
• high friction in the planetary gearbox.

We examined the first three reasons in detail above. We will consider the latter when we analyze mechanical faults.

The lack of any adjustment is due to faults:

1. In the speed control system, it is eliminated by replacing the switch or its full revision with inspection and cleaning of the contacts, checking the operability of the transistor.
2. In the direction of rotation switch or switch by operating mode - drilling, screwdriver, troubleshooting is the same as in the first case.

Any device that combines electrical and mechanical components becomes unusable over time. This is due to both operating conditions and natural wear and tear of parts. The screwdriver is no exception. In the process of operation, its mechanical components are quickly clogged with dust, the engine works in difficult conditions, and the capacity of the battery is lost. Repair of a screwdriver can be entrusted to service centers, but it is more profitable to carry it out on your own, since this process is not complicated at all.

The history of the appearance of the device

A screwdriver is a power tool. Its main purpose, following from the name, is to twist or unscrew the fastener. After the electric drill was invented in 1868, the development of the power tool became widespread. Founding companies DeWalt, Bosch, Black & Decker, Makita and Hitachi have pushed the industry forward with new devices.

The advent of the Phillips screw in 1934 created a demand for an electric tool for tightening it. It turned out to be especially in demand in mechanical engineering. The first such device was called a wrench. With the advent of batteries, the device gained mobility, and the name screwdriver came into use. Its mass production began in the early 80s..

Modern devices are constantly being improved, but to a greater extent this relates to the method of autonomy and control. The design of the device remains unchanged.

Principle of operation and main components

Before you start repairing a screwdriver with your own hands, you need to understand the principle of its operation and what parts it consists of. The main difference between a screwdriver and other power tools is the use of a mechanism that stops the rotation of the working part of the device. This happens when the maximum resistance for the instrument is reached. This value is not constant and can be adjusted. There are two types of the device:

• operating from a 220 volt network;
• using a rechargeable battery.

Regardless of the type of device, the principle of operation is the same for them and is based on the transmission of torque. It determines which fastening tool can screw the screwdriver. To increase the torque in the devices, gearboxes with a large gear ratio are used, but the rotation speed is reduced. With AC power screwdrivers, the torque value is related to the power consumption of the tool. The main parts that underlie the screwdriver device, be it Makita, Hitachi or Bison, are as follows:

• electric motor;
• push button;
• reverse speed regulator;
• chuck;
• the electronic unit;
• reducer.

The electric motor rotates the spindle at a set speed using a planetary gearbox. The torque is controlled by a coupling and a chuck or hex holder is fitted to the spindle. A removable device called a "bit" is installed in this cartridge. Controlled by a screwdriver electronic circuit and reverse switching.

Reverse occurs by reversing the polarity of the power supply. A single-phase continuous current collector motor is used as a motor. Such a motor is designed to be connected to an AC mains. The field winding is connected in series with the armature winding and is divided into two parts. One turns on before the anchor, and the other after it.

The tool uses a planetary gearbox. The gearbox includes sun and ring gears, satellites, carrier. The shaft of the electric motor rotates the sun gear, which transmits the torque to the satellites, which directly act on the carrier.

The reducer is produced in one- and two-stage type. In the second case, a double carrier connected to the shaft is used. The design of two carriers and satellites is located in the middle of the ring gear. It is fixed through special grooves on the body. Along the entire perimeter, the projections of the ring gear abut against the spring-loaded balls through the ring. The load regulation mechanism acts on the ring through a controlled spring, the force of which is changed by adjusting the regulator.

Speed ​​control is performed using a pulse circuit, assembled on a pulse-width modulation (PWM) microcircuit. The controller controls the field-effect transistor operating in the key mode. The pulse frequency is changed using a variable resistor. The resistance value of the resistor depends on the force applied to the button.

The screwdriver sleeve is a ratchet. If the load on the chuck exceeds the permissible value, then it is triggered. The force of the spring becomes insufficient to hold the ring gear, and it comes off the balls. The electric motor starts to rotate the gear idle. When switching to electric drill mode, this gear is turned off and does not participate in the work..

A rechargeable battery with a voltage of 12 V or 18 V is most often used as a power source. It characterizes the power of the device.

The battery consists of several elements installed in one housing and connected in series. The case has a special latch that allows you to quickly remove the battery.

Dismantling the screwdriver

Most often, in order to find a malfunction and repair a device, you will need to disassemble it. Since all devices are outwardly similar, resembling the shape of a pistol, their disassembly can be presented in the form of recommendations, data on the repair of the Interskol screwdriver:

Assembly takes place in reverse order.... In this case, it is necessary to ensure that all the removed elements and wires are located in the recesses specially made for them.

In order to lubricate the mechanical parts or restore the gearbox, it is often necessary to disassemble the latter. To do this, first the protective plate is removed, after which the screws are unscrewed in a circle, and the top cover is removed. Viscous materials are used as a lubricant, for example, Litol. It is important to note that it is almost impossible to carry out a serious repair of the screwdriver gearbox with your own hands, since the manufacturers do not produce gears separately. Therefore, if it is damaged, you will have to replace the entire block.

The next element that has to be disassembled is the cartridge. It is a quick-release design that is secured with a threaded connection, screw, or Morse taper. In the first method, you will need to unscrew the mount using a hex key, and then, having installed the key in the chuck, tighten it tightly. The cartridge is unscrewed by turning the key.

In the second type of connection, using a screwdriver, the screw located in the middle of the chuck jaws is unscrewed counterclockwise. Further, having installed and holding the L-shaped key in the jaws, the key must be turned counterclockwise with a sharp movement. Removing the mount using a Morse taper occurs by gentle blows to the end face of the cartridge.

Finding the cause of the breakdown and its elimination

The final breakdown of the instrument is often accompanied by preliminary events, paying attention to which a serious malfunction can be prevented: the appearance of extraneous sounds, sparks, burning odors, increased vibration, rapid battery discharge.

Having disassembled the device, you can understand which node is faulty. All device malfunctions are divided into two types:

• electrical;
• mechanical.

Each type is characterized by its own primary signs, by which the damaged part is easily calculated. Battery malfunctions are of a special kind. The nature of the breakdown is due to the fact that the battery is quickly discharged, or the device does not want to start at all.

If purchasing a new battery is problematic, you can try to disassemble it and replace the defective element in it.

The battery is disassembled by removing its latches from the grooves. Elements with a container are located under the casing. Their connection is made by contact welding. A multimeter can measure the voltage on each bank. The normal value of a charged cell is 1.2 volts. Defective elements are removed - for this they are carefully bite off with pliers at the point of contact, and similar ones are installed instead. If there is no welding, it is possible to use a soldering iron. Then the battery must be assembled and installed in a screwdriver to check.

But the problem is not always related to the battery. For example, when repairing a Bosch screwdriver with your own hands, damage (charger) is often found, not the battery. Repair of the charger consists in dialing the radio elements. First of all, the mains fuse and are checked.

Usually, when you open the memory case, by external signs in the form of blackening of radio elements or a PCB board, you can immediately see which element needs to be replaced. Most often, transistors, which are located on the radiators, and the operational amplifier fail.

Electrical damage

Most often, malfunctions in the electrical part are associated not only with the inability to turn on the tool, but also with the lack of switching to reverse mode or the ability to adjust the speed.

If the battery is working properly, and when the screwdriver is connected to the circuit, the voltage at its terminals drops, then this indicates a malfunction in the elements of the motor of the device. If the voltage is normal, the button is checked. For this, the tester switches to the dialing mode and its probes are installed parallel to the button. When you press it, the multimeter should emit a squeak, otherwise the button is inoperative. You can try to restore the part yourself by cleaning its contact groups.

Reversing is also checked using a multimeter. One probe should touch the input of the button, and the other to the contact of the electric motor. When switching the reverse, resistance should appear, if it is absent, then the damage should be looked for in the wiring. If the engine speed control does not work, then the breakdown is associated with the control transistor or button.

Checking the brushes of the electric motor is carried out visually, their wear should be no more than 60 percent. If everything is in order, you should check other elements of the engine. To measure the resistance of the windings, the motor contacts must be disconnected from the rest of the circuit. In case of breakage, interturn short circuit or short circuit to the case, the winding will need to be rewound. The anchor is checked in the same way. To measure its resistance, the tester probes are installed on the collector plates. The resistance value must be zero. If the winding cannot be repaired, you will have to purchase a new motor.

Sparking and crackling during operation are also considered electrical faults. This is due to the wear of the brushes or the slow rotation of the collector due to its clogging.

Mechanical problems

If during operation there are extraneous sounds and a wedge of the device occurs, then this indicates wear of the bushings or bearings. After disassembling the gearbox, it will become clear what could be broken. Abnormal noises can also be generated when the shaft is deformed. Such a breakdown also manifests itself when the cartridge beats. If the chuck loosens, then it is necessary to check the coupling for wear. When the tool is in operation, the teeth wear out and the clutch starts to rotate.

To avoid damage to the gearbox, it must be serviced periodically. To do this, it is recommended to lubricate all rubbing mechanical parts, preferably removing the remnants of the old grease in advance. Blockages in the structure can also affect tool RPM.

Extraneous sounds may not only be due to damage to the gearbox, but also be caused by the engine. The noise occurs when the magnet is detached or when the armature bushings are worn. To restore the work of the anchor, you can try to lubricate it with machine oil.

Thus, in case of mechanical breakdowns, the cause is easy to find, but repairs will require the purchase of new components to replace the broken ones. You will need to use a multimeter to find electrical faults.