How to check the screwdriver button by multimeter. Is it possible to measure the battery capacity
How to check the screwdriver engine?
To determine the performance of the button and engine, the multimeter is used. To perform the diagnosis of the motor, gearbox and wiring connecting the part with the trigger button, disconnect, and then measure the resistance of the anchor winding. If there are no indications, this reports the break in the winding.
- Turn on the device per unit ohm and measure the resistance of the collector lamellas in pairs.
- Then measure the resistance between the anchor body and the collector.
- Check the stator windings.
- Measure the resistance between the body and the stator conclusions.
How to measure the current power of the power supply by a multimeter?
To measure direct current, you need to set the rotary handle of the multimeter on the —, DCA or I., or press the button on the front panel corresponding to the right mode. Both alternating and direct current are measured in amperes. Therefore, the value on the screen of the measuring device will be displayed in this value.
The battery gives out 12 volts, but in order to charge it, the charge voltage must exceed the voltage of the battery. 6.55 volts will not fit here in any way. The charger must give us 13-16 volts.
Froze under load
If the battery at idle shows a relatively normal result, you can proceed to the test under the load. As an engine equivalent, you can use a resistor. Its resistance is selected for reasons of the rated current of the load of a household screwdriver, which is idle at idle (most likely 1.1.5 a), with an average load of about 5 A, at maximum. Up to 10 A. Therefore, for testing it is advisable to choose a resistor so that the current is 5.10 a. The nominal value is calculated by the OMA Law: R = U/I. So, for a 12.Volt screwdriver, the resistance of the resistor should lie within 220.127.116.11 Ohm. Power should be from 60 to 120 watts. It is difficult to find such a resistor, so can be connected in parallel, for example, 6 ten.In.Law resistors of 10 ohms and get a load of 60 W and a resistance of 1.6 Ohms.
On this equivalent, you need to load a charged battery and measure the voltage under load.
How to check a triac (with a light bulb)
Checking the battery on the equivalent of the load consisting of incandescent lamps (if there is a second multimeter, it is advisable to control the current in the circuit).
Another option is to make an equivalent of incandescent lamps, if necessary, connecting them in parallel until the desired power is reached. But here it should be borne in mind that the resistance of the thread of the lamp depends on the current flowing through it. LED devices are free from this drawback, but their energy consumption is much lower than that of traditional light sources. To gain at least 60 watts of power (consumed, not equivalent!), a sufficient number of LED elements will be required.
Under load, the voltage will pass somewhat regarding the level of idle. The degree of decline depends on the condition of the battery. There is no clear criteria for the permissible level of decrease the voltage, but it is approximately to assess the state of the battery by comparing it with the new battery.
How to check the screwdriver battery: a multimeter for performance, checking lithium-ionic and nickel-cadmium battery, banks
Falf in the battery block, this is the most common problem for owners of manual power tools. Mechanics breaks less often.
As a result of haste and negligence, when using the tool, the charge and discharge mode of the batteries is violated. The result is a decrease in the life of the batteries two to three times. You have to buy a new one.
But before buying, it is worth checking the condition of the battery to make sure that the malfunction is really in it.
Battery design and types of cans
The battery for screwdrivers is performed as a small block, joined with a tool from the rear, usually on the bottom of the handle. This is done for the optimal location of the center of gravity and convenient holding in the hand. The block is easily removed and fixed in its nest. Everything is done for convenient and quick work.
The block itself represents a plastic case with power elements inside. Since the existing chemical sources of current do not provide a typical voltage of the screwdriver (12-18 V), they are recruited in a consistent battery. The conclusions of the elements are connected by a metal flat tire, which is welded to them with contact welding. This method is least of all heats the elements during assembly.
Thus, the battery is a non.Combination. In developed countries, they are disposed of without repair. Elements, or as they are simply called, “banks” are also made unlimited, and also sometimes contain harmful substances. In shape, elements are cylindrical or rectangular.
In cylindrical elements, it is usually Ni-CD or Ni-MH-the electrodes, along with the active mass and the separator, are rolled into a roll, and in rectangular ones, they are typed in a package, or sometimes also performed in the roll. The purpose of any of the methods: to maximize the area of the electrodes, which gives the maximum of the selected current with a minimum of heating. This provides high specific power of the element.
The lithium-ion elements are produced both in cylindrical buildings and in flat, and lithium-polymer with tape or wire conclusions-in flat.
In general, the design is similar to oil capacitors, only there the electrodes are called gaskets, and they are separated by an non.Conductive dielectric. Oil. In the case of batteries, on the contrary, the aggregate conducts a current, this is an electrolyte solution.
608 Multimeter Probes. Needle Tipped CAT-II 1000V 20A Shopping Review
The operation of the battery is associated with corrosion of the electrodes, and other irreversible chemical processes. Gradually, he loses efficiency and becomes unusable. Incorrect charge-discharge mode accelerates these events.
Remember: Nickel-cadmium batteries must be discharged to minimum voltage, and only then put on charging. And lithium-ionic-on the contrary, recharge more often. This extends their service life.
Corrosion violates the shape of the electrodes, leads to the breaks and punctures of the separator and the further closure of the cathode and anode. This increases the self.Discharge. The formation of unimportant compounds in large quantities leads to irreversible growth in internal resistance. Such compounds are obtained in the course of side chemical reactions that are inevitable and limit the service life.
Guide to action
Before you recognize the battery unsuitable for use, you need to check it for performance.
Tools for verification
To check the battery, it will be necessary to have a voltmeter, ammeter, connecting wires and devices for capture contacts: clamps like crocodiles or clamps. Sometimes the design of the contacts of the battery block does not allow you to connect devices without disassembling the case. It is very possible that you will have to solder. Here is the list of necessary:
- Charger (original or compatible);
- Multimeter (or better than two);
- Resistance 4.7 10 Ohms for power from 5 watts or more;
- Car lamps on 12 V, several pieces;
- Mounting wires, section 0.5 mm.Sq, 1.5-2 m;
- Sharp knife;
- Solder with solder and flux.
Instead of a native charger, there would be a very suitable laboratory power supply, with a voltmeter and an ammeter for current several amperes and a voltage of several volts above the value of the tested battery. For example, a zero from a car if it has good built.In devices for measuring current and voltage.
To check the screwdriver battery, the multimeter is most often used, it is also suitable for measuring the battery capacity.
In addition to everything else, you need to prepare a convenient workplace with good lighting, remove flammable fluids and objects away.
First you need to install the type of battery. It is written on her case. The nominal voltage and container in ampere hours or sometimes watt hours should also be indicated there. The voltages used can be from the row: 9.6, 10.8, 12, 14.4, 18, 24, 36 V. Type of batteries and voltage rates make it possible to determine the number of cans inside the block:
|Electrochemical system||Maximum voltage, in||Nominal voltage, in||Minimum voltage, in|
A typical battery discharge schedule will also be useful:
The working battery after the charge shows the maximum voltage UMAX. After a while, it decreases to the nominal unom. Then the battery gives the current for a long time, on the interval t0 t1. During this period, as a rule, the rated voltage slowly decreases to the minimum UMIN. At the end of the discharge, the battery begins to give a poorly current, and the tension quickly begins to fall.
A voltmeter without a load of a normal battery should show a voltage close to the face value. If the voltage is less than the multiple of the rating of the cans used, it means that one or more cornered.
This can mean a deep discharge, and even a chain break. Therefore, this check will be a check under load.
Express test method: measure u at the batteries of the battery
This method is even simpler, but with its help you can make a primary idea of whether the battery is in order. If we hold measurements U without connecting the load, we will get an indicator equal to the “idle” tool.
For example, if we have 12 parts with a voltage of 1.2 volts each in the battery, and the worker’s indicator U is 14.4 volts, U “idle” will grow up to 17 volts. If the “idle” voltage is less than the indicated, this means that there are “banks” in conjunction that failed and need to be replaced. Also, a decrease in idle voltage may mean that the battery is not fully charged.
Checking the screwdriver battery
To determine the real basic parameters of the battery, a check is carried out.
Battery elements can change their capacity
Checking the screwdriver battery is carried out when fully charged. The full check takes place in several stages.
Tools for verification
Checking the electric drive can be done using:
The first stage of verification
So, half an hour after the start of charging, the voltage value will be 13 in. If you measure in another half an hour, then the voltage will be 13.5th century. 2 hours after the start of charging, the voltage will already be about 14 in. This suggests that the maximum is achieved. In a fully charged battery, the voltage has a value of equal to 17 in.
You can evaluate the quality of the drive by measuring the current during the charging process. If the battery is in good condition, then it is characterized by steady current growth of 1 hour during the charging process. Passing the value of the mark of 1 A indicates the normal functioning of the drive.
Some elements in the battery are non.Working
Based on the results of the first check, you can make an initial impression of the performance of the battery elements. This will help to establish the need to disassemble the battery.
Checking under load
To answer the question, for what time the battery is discharged, the drive should be checked under load. The load must be selected based on the power of the drive. If it is unknown, then it is believed that the load power is equal to half the work of the current force that is given the battery during operation, to the voltage of the drive. As a rule, this value is taken equal to 35–40 watts. Thus, as a load, you can use an automobile headlight (35 W) or use a 12-t-lamp with the same power.
The battery has a damaged element
Checking elements of the drive
So, let it turn out that with the help of preliminary checks, the presence of faulty elements in the drive was established. Then it is necessary to disassemble the battery and extract sequentially connected nutrition elements. “banks”. As mentioned above, the battery consists of 10-12 such elements with a voltage of 1.2 century.
After inspection, the voltage measurement of each of the “cans” should be measured. The voltage of one element should not be less than 1.2 century. When conducting measurements, the battery elements should be disconnected from the connections with all kinds of sensors. The measurement device is connected to the poles of the battery. “Banks” with reduced voltage are subject to replacement. If the simple measurement was not detected with simple elements, “banks” should be measured under load.
The ability to normal functioning of each battery can be checked by comparing the “banks” in internal resistance. The value is determined by dividing the working parameters voltage into current strength and deduction of load resistance.
As a load, take a resistor with a resistance of 10 Ohms
For a better understanding, we give approximate calculations. Suppose, during the measurement under the load, data for one “banks” were obtained: working voltage. 1.19 V and labor current. 112 mA. Before making the calculation, do not forget to translate the value of the current force from ma to a. 0.112 a. We make appropriate actions (1.19/0.112). 10 = 0.63 Ohm. Recall that the resistance of the resistor load subtracted in our expression (10 Ohms).
Checking the remaining parameters
Each type of battery has a certain value of self.Discharge.
Checking the power elements for the presence of the “memory effect” is carried out by fully charging the battery and its full discharge. Produce several cycles of charge-discharge (3 or 4). The battery discharge can be carried out using a lamp in 12 in. In the course of actions, the residual operating voltage and idle voltage are measured. After repeated repeating the cycles, the “memory effect” will disappear.
Varieties of batteries
To date, the most common nickel-cadmium type of battery. Its undoubted dignity is considered:
The maximum voltage of an individual element reaches 1.38 volts.
Nickel-metallogid type is actually a competitor to the aforementioned type of battery. True, its parameters are much worse, but the elements are completely safe from an environmental point of view.
The named batteries must be sent for storage in a charged state, otherwise after a month they will fail.
Relatively not so long ago, the battery began to produce for screwdrivers:
They are distinguished by a small size and a large container. There are two disadvantages:
Malfunctions in the drill electric motor
Most often, when the electric motor is out of order, a very strong engine heating appears and the pungent smell of burning or smoke appears.
When you press the start button, the engine emits a strong hum, while the rotor does not spin and smokes, that is, the drill buzzes but does not twist.
At home, it is not possible to repair neither the stator nor the rotor, so you should give them to the repair workshop or buy new spare parts.
Photo-6.Visual examination of the electric motor.
To determine the failed part, the masters usually use measuring devices, but most often visual inspection gives good results.
It is not difficult to notice the burnt stator wires or other changes in the appearance of the rotor.In the case when the visual inspection did not give the desired results resort to inspection using measuring meter and ohmmeter devices.
The windings of the stator or anchor are most often subject to the following characteristic damage:
3.Damage to the magnetic circuit or breakdown on the case.
It is possible to determine the reason for the malfunction of the stator or rotor winding or rotor, but it is possible to carry out high.Quality repairs without special equipment and knowledge is not possible.
In order to determine a breakdown on the case, a metometer with a measuring voltage of at least 100 volts is used.To do this, the megometer probes relate to the output of the winding and the magnetic circuit.If the device shows the voltage resistance less than 500 MOM, then with a high probability we can say that there is a break in the winding.
Frigidaire Fridge Not Cooling and The Easy Fix
Photo-8.Determining the cliff in the stator winding.
The cliff in the stator windings can be determined using an ohmmeter.To do this, it is connected to the ends of the winding and carefully monitor the readings.If the resistance is absent in the readings of the device, then there is a break.The electric interitral breakdown of the rotor (anchor) is usually determined visually.
Interpretation circuit can be detected in sections of wires of the winding.The wires can be crumpled, strongly pressed to each other or between the turns there are conductive objects or particles.In case of detection of such malfunctions, you should begin to eliminate.If this is not possible, then the part should be replaced with a new.
How to check the integrity of the wire in the mode of determining the resistance
In multimeters, where there is no call function, checking the integrity of the wire can be carried out in the mode of measurement of resistance.
In this case, the probes are connected as well as during the call, and the device is put into the mode of determining the resistance (Ω).
You need to start measurements on the minimum threshold of the device scale. For example, 200 Ohms. All actions are the same as when calling. You just need to monitor the readings of the device. If the wire is safe, then the value of its resistance is displayed on the display. If there is a cliff, then the resistance is not displayed (OL. The state of overload).
STURM screwdriver Scheme Scheme of button connection
Screwdriver. A mobile tool that facilitates work with fasteners and threaded joints.
Until recently, battery screwdrivers could only be found in the arsenal of professionals, but with the advent of inexpensive inexpensive household models, their popularity increased sharply.
Unlike expensive professional tools, budget analogues have a smaller resource, which more often fail.
One of the weakest places of household screwdrivers is the start button and the reverse switch. As practice shows, it is they who break most often.
Over time, the tool ceases to respond to any manipulation. Often there is a problem of the opposite nature when the motor begins to work spontaneously.
How to Test a Car Battery With a Multimeter ( Voltage Cold Cranking Amps)
In some cases, to eliminate the defect, it is enough to disassemble the tool and clean, although more often you need to complete Replacing the screwdriver button. Both in the first and in the second case, you can eliminate the problem with your own hands. About everything in order.
How the screwdriver button works
The fundamental electric circuit of the screwdriver, in particular, its buttons, is determined by the main functions:
- Starting the engine when pressing and stopping it after the owner of the device releases the button;
- Reverse, that is, changes in the direction of twisting of the nozzle, it is especially convenient to use for repeated assembly and disassembly operations;
- A smooth speed set so as not to spoil the screw head and maintain a decorative appearance of the material where it is screwed;
- Control of the speed of rotation to drown a self.Tapping screw to the required depth (for example, leave it on a flush with the surface).
Based on the device for turning on/adjusting the work of the screwdriver, individual modules are usually carried in various conditional compartments:
- The button is located directly at an average level to conveniently lie down under the fingers when taking the tool in the hand. It stands on the guides, which moves when pressing. Sliding smoothness is achieved thanks to the spring that propagates it from the inside;
- The reverse is carried up. Classically, the change of direction is inverting polarity. The engine will rotate in the opposite direction, then through the reducer inverted torsion will be transmitted to the nozzle. The wires going to the engine also go up;
- The unit, which is responsible for turning on, is demolished down, closer to the battery or exit for connecting to the network.
Option with additional options Additionally, the components of the screwdriver can be included:
- The speed switch button is low/high speed, less often 3 positions;
- Button for activating the drilling mode, if the corresponding function is put on a separate regulator, and not integrated into the slip.In mechanism;
- Battery control module and wires to connect to the battery;
- Additional wires that are not even used.
How to fix the screwdriver button if it does not work. Detailed instructions
You will need the following tools for the diagnosis and repair of the screwdriver:
As a result of the active use of any power tool, dirt inevitably accumulates inside his body.
- Disassemble the tool case. To do this, disconnect the battery, unscrew all the screws (they can be hidden behind the decorative plates that need to be removed).
- Check the operability of the motor. To do this, disconnect the two power wires from the control unit and connect them to the battery contacts (the engine should work).
- Disassemble the screwdriver button. To do this, squeeze the plastic latches and disconnect the two parts of the button case.
- We perform a visual inspection of the button for pollution and damage.
- Next, you need to carefully assemble the screwdriver button, reinstall and test.
If cleaning the control unit does not work, you must replace the entire buttons block.
- Disassemble the screwdriver (the process is described above);
- Install a new button on the old one;
- Connect the engine to the terminals of the button (in this case, polarity is not required);
- Gather a screwdriver, gently placing the wire into the case.
It is very important to choose a button for a specific screwdriver model, because with all external similarities and visual accordance, the part may not be placed in the grooves. As a rule, new buttons are sold complete with battery terminals and transistor.
Before primary measurement, you need to try to carry out the charging function to the rated voltage. Then you need to wait about an hour to stabilize self.Discharge processes and measure the voltage of the battery. It should be equal to the voltage indicated on the case, but you should not trust this figure 100%. It often has a marketer disposition and can be somewhat overstated. Therefore, it is better to find the tension like this: take the voltage of a single element (it is dependent on the type of battery) and multiply it by the number of cells in the battery. If the amount is incomprehensible, then you need to take the frequency so that the final voltage does not exceed the indicated on the case.
So, if on the body of the screwdriver it is indicated that the lithium-ion battery has a voltage of 20 V, most likely this means that it will actually on a completely charged battery 3.75 = 18.5 volts.
If the voltage is lower, this means that there are lagging elements in the battery. Another option. One or several cans in a cliff and when turning on alternately, they do not allow the rest to be rechargeed (the charging circuit is interrupted).
If the voltage of the battery, which has passed the charging function, is below the multiple of one or several voltages of a single element, there is reason to believe that there are one hundred percent faulty cells. So, if the NIMH batteries for a face value of 14 volts (expected 1,211 = 13.2 volts) in the fact of idle 12.0 volts, in other words, the grounds to consider a malfunction of one can, and if 10.8-then 2-uh.
REPAIR OF THE WORkens engine
With long work with a screwdriver, bearings can be worn out or clogged.
Before the assembly of the screwdriver of the screwdriver using a thin wire that serves as a clamp, each brush is diverted in the brush holder, the lid is installed in the same place. At the same time, brushes release and envelop the housing at the edges, which contributes to the best pressing of the back cover.
If the screwdriver has been working for a long time, then this may be accompanied by the process of curvature of the shaft related to the gearbox due to strong loads and pressing the tool. The cartridge, blaming the shaft, sometimes causes a strong beating during the operation of the device. Supporting sleeve or shaft bearing can be very worn out. As a result of damage to the sleeve or only the bearing, and not only them replace the shaft.
Sometimes the engine is not possible for a certain fraction of a second, that is, its sharp stop occurs. This reason may be the failure of the gearbox. Often a malfunction occurs due to a breakdown of a pin that serves as a mount to satellite. It is possible to replace the drive or entirely a gearbox that may fail if the teeth of the gears are worn out.
If, after all the above operations, the malfunctions were not detected in the device, then it is necessary to verify the anchor condition and the serviceability of the engine brushes. In this case, the engine should be disconnected from the switch button, and then measure the resistance by attaching a tester of any kind to the engine wires. If the resistance in the circuit is completely absent, then this may indicate that the brushes are worn out. The malfunctions in the anchor of the engine are not excluded, which may be associated with the gap of the winding. At the same time, such types of problems can rarely meet.
If the engine anchor is completely burned out, then the device engine is subjected to the full replacement. If only the engine brushes occurred, then it is better to make the repair of the device yourself. Before starting the repair, it should smoothly open the body of the screwdriver engine 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 anchor’s bushings were worn out at the expense of the magnet, which came off and began to contact with the anchor. Dripping a drop of special oil to the sleeve, you should turn off the engine to wait until the oil has dispersed through all the bushings. At the same time, he still requires replacement over time.
In this topic, we will consider a malfunction of the screwdriver, get to know how to check the screwdriver and then. For personal photographs, an explanation will be given that will allow you to learn some details in checking the power tool circuit. Let’s start with the power of the screwdriver.
How to independently connect the drill button?
Although this process is quite complicated, you can do all the work yourself, following some important rules. For example, remember that the opening of the lid can lead to the fact that all parts and untouched parts will simply fall out of the case. Of course, this should be avoided, because then it will be quite difficult to assemble the device. To do this, you can gradually raise the lid, noting the exact location of the parts on paper.
The button is restored as follows:
- First, select the casing latches, and then carefully tighten it;
- All rusty and darkened terminals are cleaned of soot, for which you can use alcohol or sandpaper;
- We re.Collect the tool, we make sure that all parts of the device are in place, and check the performance of the drill. If nothing has changed, we change the detail;
- We fill the speed control regulator, and therefore, when the part fails, we simply replace it;
- Frequent breakdowns. Abrasion of the working layer under the rheostat. It is better not to repair it, just waste time, it is better to buy a new one and replace it.
Many are wondering where to get such a scheme? First of all, he must buy it with the help of a tool, but if the scheme does not exist or you have lost it, you will have to look on the Internet. After all, only with its help you can fix it without errors. By the way, the speed control button and the reverse button are located in different places, so they will have to be checked separately.
Read what torque is better for a screwdriver
Preparation for work
To conduct diagnosis and subsequent repair of a screwdriver, we will need the following tools:
The reason for the repair was unstable operation of the power button. With a full press, the screwdriver engine stopped working.
To diagnose a malfunction, it is necessary to disassemble the screwdriver body. For this, remove the battery, with a flat screwdriver, remove the decorative overlay on the housing (under it there are screws of the housing). The overlays on plastic fasteners are fixed, which are quite easy to break.
Unscrew the screws with a crucible slot with a screwdriver with a cross.Shaped slot (in our case 8 screws) and carefully disassemble the housing.
When opening it is clear that the power transistor was melted. The transistor is involved in the smooth control circuit of the screwdriver revolutions. When the button is completely pressed, the engine power circuit closes directly, providing operation at full power. Most likely the problem is in the button.
You need to make sure that the engine is about. To do this, disconnect the two wires of the engine power from the button, pull them out and press the narrow flat screwdriver to the button’s spring contact.
In order to get to the second wire, we take out the battery contacts and a button from the grooves in the screwdriver housing.
We connect the screwdriver engine to the battery contacts (polarity is not important). Check rotation.
If the engine is working, a button is necessary. It is important to choose a button for this screwdriver, since in size not all buttons can become in the grooves. The button is sold with the battery terminals and transistor.
To do this, connect the engine to the terminals of the buttons. At this stage, the polarity of the connection is not important.
Connect the battery contacts of the new button to the battery.
Press the button and check the direction of rotation of the engine. We pay attention to the position of the direction of the direction of the direction. This is necessary in order to choose the usual position of the rotation direction button for you. If the situation does not correspond, it is enough to change two wires from the engine with each other.
We collect the body of the screwdriver in the reverse sequence. We put a plastic pusher in its groove and connect it to the button lever. Install the contacts of the battery in the groove of the case.
Install a transistor with an aluminum plate in the groove.
Carefully place the wires in the case, given all the grooves and latches. This is necessary in order not to kill the wires during the reverse assembly process. The case should get together easily and effortlessly.
We tighten the screws of the body mounting with a slight effort and install the plastic lining.
How to disassemble
Dismantling of a screwdriver is performed on a table or other even surface to avoid loss of parts or fasteners.
To disassemble the screwdriver, you first need to extract the battery, and then unscrew all the screws. Then the case is carefully opened, trying not to damage the structure. If difficulties arise, you need to inspect the device again. Perhaps somewhere the fasteners remained or parts are connected by brackets that need to be removed.
After the case is open, the parts are removed alternately, they lay them out on the table in the order in which they were extracted. You can take several photos so as not to make a mistake in the process of assembling the technique.
Strong vibration during work, uncharacteristic noise or other signs are reported about the breakdown of this node. For the repair, you will need to disassemble the screwdriver gearbox. It includes ring gears, gears-sodelites, as well as drivers. All parts are alternately extracted from the body, then carefully cleaned, lubricated.
The procedure is carried out on a flat surface, extracting all the details, laying them in the correct order, so as not to experience problems with reverse assembly.
The disassembly itself looks like this: the cartridge is removed, the case is disassembled, the gearbox is separated from the engine. Next, the plate is removed, all parts are extracted from the case, the bolts are removed, connecting haltor halves. Pliers are adjusted to the diameter of the spring to improve the inclusion of the transmission. Next, the coupling is disassembled. The stop ring, washers, and bulk bearing are removed. The shaft is extracted.
Faulty elements after disassembly change to new. Sometimes, for example, with a curvature of the shaft, it is necessary to purchase a new gearbox.
If the motor does not work, the problem is usually related to brushes, less often. With an anchor winding. In the first case, brushes change to new. In the second. You need to change the engine itself. The gear pressed on the shaft of this node remains intact, it must be disconnected with a special puller or improvised tools. Then the part is put on a new engine using a hammer and a solid surface.
The repair of the screwdriver button is usually inappropriate, but sometimes it is enough just to disassemble it and carefully clean it. Conventionally, it includes three knots: