DIY Hitachi screwdriver gearbox repair

In detail: do-it-yourself repair of a Hitachi screwdriver gearbox from a real master for the site my.housecope.com.

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.

Video (click to play).

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 operates 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, this 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.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 Hitachi screwdriver gearbox 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 Hitachi screwdriver gearbox 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.

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. Image - DIY Hitachi screwdriver gearbox repair

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.

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 motors and brushless motors can be installed (do not have electric brushes).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.

Like any other tool, a screwdriver sometimes needs repair. In such situations, some craftsmen replace this tool with a drill.But at the same time, it should be understood that screwing or unscrewing bolts and screws with a drill is quite inconvenient and has to be done with considerable force, therefore, it is very important for a home craftsman to learn how to troubleshoot a screwdriver with his own hands.To help home craftsmen in this matter, in this article we will tell you about the device of the screwdriver, what malfunctions can occur in the operation of this tool, and also in what ways they can be eliminated. Image - DIY Hitachi screwdriver gearbox repair

Before approaching the issue of instrument malfunctions, first of all, it is worth knowing what structural elements it consists of.

You can illustrate the device of a screwdriver using the following image.

To view, click on the picture

As you can see from the figure, the tool consists of the following structural elements:

Electrical engine;
gear mechanism;
reverse and button to switch it;
the force regulator is presented in the form of a ratchet;
chuck for fixing bits and drills;
start button;
speed regulator, in other words, the speed of rotation of the working shaft.

It is also worth understanding that the schematic diagram of the device of screwdrivers of such popular trade brands as Makita, Bosch, Hitachi, Aeg does not have significant differences.

Read here about choosing a nutrunner.

From this article you will learn what a grinder is.

In order to perform a high-quality repair of a screwdriver, it is necessary to prepare the following materials and tools in advance:

multimeter;
crosshead screwdriver;
hairdryer;
sandpaper;
used toothbrush;
technical alcohol;
lithium based grease.

To disassemble the screwdriver, you must perform a number of the following sequential operations:

disconnect the unit containing the battery;
use a Phillips screwdriver to unscrew all the screws that connect the two parts of the tool body;
the electric motor, gearbox and all other structural parts are removed;
the reverse switch button is removed;
the force regulator is dismantled;
the gearbox is disconnected from the motor.

Screwdriver disassembly diagram, click on the picture to enlarge

After completing the specified procedure, we can say with confidence that the screwdriver has been disassembled.

The main breakdowns of a screwdriver, which can be repaired with your own hands, are in the following important aspects:

The instrument does not turn on.

The reasons for this malfunction may be the following:

the switch has broken;
burned out one of the wires of the electrical circuit;
the battery is out of order;
wear of graphite brushes;
combustion of motor windings.

Learn about the jigsaw in this article.

To remove the above malfunctions, you must perform the following steps:

replace the switch;
find an open circuit in the electrical circuit and level the problem;
purchase a new battery;
replace the brushes of the electric motor collector;
rewind the motor windings.

The reverse stopped working.

As a rule, the reasons for this type of breakdown are the following facts:

burned contacts;
switch malfunction;

When there is no adjustment of the power of rotation of the screwdriver, then in this case there may be the following reasons:

power button malfunction;
defect in the functioning of the transistor.

To troubleshoot, it is worth performing the following operations:

check the contact group of the power button, clean all connections, and in some cases, replace this unit completely;
if the cause of the malfunction is a transistor, then it must be replaced.