DIY screwdriver button repair

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

A screwdriver is one of the most essential tools for a modern person. With its help, you can perform a lot of different household chores. It is indispensable for both global construction and local repairs. However, many parts of the device may fail sooner or later. This is most often due to improper use of the power tool. Sometimes you may need to repair a screwdriver with your own hands.

Diagram of a cordless screwdriver device.

Yes, of course, in most cases it is easier to contact a specialized workshop, but it can take a lot of time, and repairs can cost a pretty penny. In any case, minor breakdowns can be eliminated on your own. For example, the start button can be repaired. She often breaks down. How to repair a screwdriver button with your own hands will be discussed further.

Wiring diagram of the screwdriver button and the power transistor.

To begin with, you should think about how easy it is to make repairs by spending a minimum of money. Of course, a complete replacement of a structural element, and in this case a button, will save money and bring the device to its original level.

The screwdriver itself is quite easy to disassemble. To do this, you just need to take a Phillips screwdriver and unscrew all the screws around the perimeter, which are located here as fastening material. Having disassembled the device, you can find that it has a fairly simple structure. There is a motor, a gearbox, a button with two wires that connect it to the battery, as well as 2 wires that connect it to the engine.

Video (click to play).

So, the simplest repair method is to replace the button; it is simply soldered off from the motor. Then the connector is removed that connects it to the battery. Such a structural element is quite inexpensive. It can be purchased today for about 300-500 rubles. Further, the wires from the engine to the button are soldered in place, and those that go to the battery are installed together with the connector. The battery can now be reinserted and the instrument can be checked for functionality. If everything is in order, then we can safely state the fact that all the repair work was carried out correctly and competently. Now you can assemble the screwdriver. There is an even less expensive repair method, in which the button does not change, but is restored.

Electric diagram of the screwdriver button.

Of course, before proceeding directly to the repair work, it is imperative to select all the most necessary tools and materials. These include:

knife;
flat screwdriver;
Phillips screwdriver
soldering iron with rosin and solder;
cotton wool.

Basically, these are all the tools and materials that you may need to carry out the work. The list is not that long. All this can be at home with any man.

Diagram of the gearbox of the cordless screwdriver.

Well, now let's go directly to the recovery process. Generally, the button is not easy to acquire. Often you have to make a pre-order at a service center and then wait several weeks for it to arrive. That is why DIY screwdriver button repair is relevant.

It can be noted right away that there is no need to unsolder the wires that come from the button. They will not interfere with the process of assembling and disassembling a structural element.So, the screwdriver was disassembled using the same technology that was indicated above, which means that the button is in close proximity, that is, various repair work can be carried out with it. To begin with, it is worth removing the pressure mechanism. This must be done very carefully so that the base is not damaged.

The clamping mechanism is often red, but this all directly depends on the specific model of the power tool.

Electrical components of the screwdriver.

It is not necessary to remove the clamping mechanism with a sharp jerk. It is best to use slow rotational movements clockwise or counterclockwise. Here, too, it all depends on the specific model of the screwdriver. Now you can proceed directly to the repair, or rather, to identify the problems that led to the malfunction.

Any push-button product of this kind has a protective mechanism. It needs to be removed too. To do this, you will have to use the tools at hand, namely a flat screwdriver and a knife. Moving in a circle, you need to release the latches. This is done very simply, so it should not cause any problems in the work. Now you can remove the button cover, under which the reverse mechanism is located. In fact, the inclusion element itself is not yet visible. You still have to get to it.

To do this, you need to pick up a soldering iron and rosin. It contributes to the heating of the soldering point, which leads to the separation of the parts. In this case, you need to divide the two compartments between each other. First, the soldering iron is immersed in the rosin, and then leans against the separation. As a result of these manipulations, the mechanism from a single whole is divided into two parts. Only now you can try to get close to the switch. For this, the cover is removed from the corresponding compartment. Now the compartment for turning on the screwdriver becomes completely open to the human eye.

Stages of disassembling a screwdriver button.

Next, you need to carefully remove the mechanism from its rightful place, while holding the return spring, which is installed here without fail. Now you can look inside. Each person at this moment with the naked eye is able to see that all contact pads have worn out during operation. The main reason for this is most often the poor quality of the metal used to create these sites. As a result of the fact that the material is destroyed, its dust gradually settles between the contacts. This leads to the fact that those surfaces that were once dielectrics become electrical conductors. This is often the reason for the spontaneous switching on of the power tool.

Since the cause has been identified, accordingly, it remains only to eliminate it. This is done quite simply. With the help of the most primitive and simple materials, it is worth removing dust from the surface of dielectrics. For this, you can use the most ordinary cotton wool. It is advisable to pre-moisten it in alcohol. If this method does not help to remove the remaining dust, then you will have to use a knife. With it, you can try to scrape contacts. Some people use sandpaper for these purposes, but this is not recommended, since irreparable damage can be caused to the contact surfaces. That is, in this case, it turns out that the repair is not for the good, but reduces the entire result to a negative value.

Now we can state the fact that the button repair work has been completely completed. It remains only to collect the entire mechanism and tool. This is done in the reverse order. To begin with, two structural elements are soldered together. Then they are installed in their rightful place.

Comparative table of characteristics of screwdrivers from different manufacturers.

Now it is important to correctly install the return spring together with the pressure mechanism. It is worth immediately checking how the button is pressed.If it sinks, then it is possible that the technology was violated during its assembly. This leads to the fact that it simply will not work. We'll have to disassemble everything again. That is why you should be guided by the saying - measure seven times, and cut one off. This is the only way to return the original appearance to the push-button mechanism.

Then you can proceed to testing the functionality of the button. To do this, a battery is installed in its rightful place, and the power button is pressed. If everything is done correctly, the screwdriver should start. This suggests that the tool can be assembled. Previously, all structural elements are installed in their rightful places, and only after that the two halves of the tool can be connected together. Everything is returned to its place and connected with the same screws that were removed when the screwdriver was disassembled.

So, all the work has been completed, which means that we can summarize some of the results of all that was discussed above. As you can see, there are two main methods of restoring the functionality of the screwdriver button. The master himself must choose one of them. Of course, you can always contact the service center, but this is at least unprofitable. It's always best to do it yourself.In this article, we will consider a screwdriver from the well-known Makita brand, describe its technical characteristics and general structure, talk about the main problems and malfunctions that arise during the operation of the tool, as well as how to diagnose a breakdown and repair one or another element with our own hands. screwdriver.

Consider the device of a screwdriver on a specific model 6271D. The diagram of this model is shown in the figure below.

The diagram shows:

Shift lever
Body assembly
Nameplate
Screw
Spring
Reverse shift lever
Start button
Contact terminal
Screw
Keyless chuck
Gearbox assembly
Electric motor
Screw
Body assembly
Charging unit
Battery

A modern screwdriver is a high-tech device. Important structural elements:

Removable battery
Rubberized handle grip
Powerful electric motor
Metal planetary gearbox
Soft start button
Reverse switch button
Torque regulator

These are the main components of the screwdriver design, which are included in the basic package of any screwdriver model.

To disassemble the screwdriver, you need a Phillips screwdriver and some personal time. To disassemble the screwdriver completely, you need:

unscrew the screws securing the case;
remove the composite start button mechanism;
remove the electric motor together with the gearbox;
disconnect the gearbox from the engine by unscrewing the bolts holding them together.

To disassemble the battery of a screwdriver, you need to loosen the bolts connecting the body, or separate the body joints on an adhesive basis using a soldering iron. Inside the battery there are several nickel-cadmium batteries with a certain capacity and carrying a charge. In case of battery repair, they need to be replaced with new ones.

The chuck is changed with a screwdriver and a hex wrench. First, use a screwdriver to loosen the fixing screw in the chuck by turning it clockwise. Then the hexagon is inserted, the reverse button is turned on, clamped, and then the chuck easily yields.

The most frequent breakdowns of a Makita screwdriver are as follows:

The screwdriver does not turn on. Here and so everything is clear. The first step is to inspect the battery, as well as the contacts and connections in the case, and the wiring. A multimeter will help you to check.

The reverse button does not work. This means that you cannot either tighten or remove screws and bolts. Here you have to test the resistance of the button with a multimeter by placing test leads on the input and output wires of the button.

The speed regulator does not work. In this case, the revolutions will be either constantly reduced or constantly overestimated. The regulating transistor or brushes may be to blame. A visual inspection of the parts is required.

The on / off button of the instrument is a complex electronic mechanism. It consists of several elements that make it up:

start buttons;

reverse buttons;

buttons for switching the speed of revolutions;

buttons for soft start of the engine.

When repairing a button, you first need to disassemble it by unscrewing the screws that secure the case and disconnecting the battery. After that, you must check the connections and contacts for dirt, clean them. If cleaning the contacts did not help to fix the problem, the button should be replaced as a whole.When repairing the charger, it is necessary to unscrew the screws securing the housing covers. Inside there is a printed circuit board with contacts. First you need to check the transformer with a tester. To do this, you need to measure the output voltage. Then the cable should be ringed to exclude its fracture. Then the primary and secondary windings of the transformer and the fuse are checked. You need to assemble it in the reverse order.

The brushes used for the screwdriver are graphite-based. Their cost today varies between 2–5 USD. e. They are located in the motor housing and are two graphite cubes fixed on metal plates. With intensive work, they wear out and wear out.

When repairing with your own hands, they can be filed out of brushes from another tool, for example, a car starter. After grooving, they should be inserted into the brush holder and put in place by assembling the motor.

Such a chuck is used for clamping bits with a cylindrical shank. This cartridge features ease of installation. It is installed literally with one movement of the hand. It is used for drills with a diameter of one to ten millimeters. It is a movable structural member in the tool and therefore breaks frequently. To disassemble it, you need to read the tips described at the beginning of the article for disassembling the cartridge using a hex wrench and a Phillips screwdriver. The price of this product is about $ 20. e.The material in this article is voluminous. Here we described all the possible problems that arise during the operation of Makita screwdrivers, told how to eliminate them on our own, separately talked about the various structural elements that make up the basis of any screwdriver. The materials of the article show the diagrams of the gearbox and the general device of the screwdriver. We hope that the information will be useful to you.

Now you need to remove the protective cover of the button, for this you need a knife and a flat screwdriver. Prying in turn and pushing out the latches, in those places where the arrows in the photo indicate, we remove the cover and the reverse compartment appears to our eyes, but the mechanism for turning on the screwdriver is not yet available.

Now you have to use a soldering iron and unsolder the two elements from each other, as shown in the figure. And now, slowly, we take out the element at number 1, which is located on top, after which you can safely remove the cover that covers the screwdriver activation compartment.

Now, neatly, we take out the switching mechanism from the case, holding the return spring.

Looking inside, you can visually see that the pads are erased. The reason that the contact pads are erased is the low quality of the metal. As a result of the fact that the metal dust is in an enclosed space, it settles between the contacts, as a result, a conductive surface is formed on the dielectric surface and a current begins to flow through it, as a result of which spontaneous rotation occurs.

And since the reason for this phenomenon is clear, that is, the way and solutions to this problem.

In order for the self-propelled to stop, you need to remove the metal dust between the contacts, cotton wool, or if you can't scrape it off easily with a knife.

After such a simple procedure, we assemble the button in the reverse order. We install it in place in the screwdriver body and assemble the body. After such a repair, the button will serve for some time, but you still have to buy a new one!

The site "I do it myself - I'll tell you how to do it for you!"

For animation of any toys, for a gift or just for creativity, you can assemble a "running fire" scheme.

The effect of creating lights running from the center to the edges. Very similar to the rays of the sun.

Specifications:

Number of channels - 3;
Number of LEDs - 18 pcs;
Usup. = 3 ... 12V.

Today the washing machine is one of the indispensable helpers in the house. Everyone can install the washing machine independently. If you previously had a washing machine and you have all the necessary communications (water, drain, electrical outlet), then the installation of a new washing machine is greatly simplified.

Since I am an avid motorist, I am interested in everything related to cars. Each car owner is faced with the task of protecting the car body from corrosion. I read about this original method before, even at the beginning of the last century it was used to protect the hulls of ships. But this is the first time I've come across such a miracle of technology with a commercial application. Reading advertisements in newspapers, I came across an advertisement "Electrochemical protection of a car body from corrosion", after reading a short article, I decided to find out more in the car service itself. More details ...

The Makita DF330D drill suddenly stopped working. When you press the button, only the backlight LED lights up, no sounds are heard.

I disassembled the drill. The button "rang" with a multimeter. It turns out like this (sorry for the terminology):

(1) if the button is released, then there is contact only between the positive terminal of the battery (red wire at the "input" of the button) with both (!) Terminals on the engine;

(2) if the button is pressed, then the contact is only between the positive terminal of the battery and one (red) terminal of the engine, the second terminal at the "exit" from the button is not connected in any way with the battery.

In other words, if we imagine that a pair of wires (red and black) enters and exits the button, then in the first case the red input is connected to both outputs, the black input is not connected to anything, and in the second case (the button is pressed) the red is connected to red, black torn.

It seems to me that this should not be so.But changing the entire switch is expensive (about 2,000 rubles, almost a third of the cost of a drill), and I can't repair the button, because I don't even understand how it can be disassembled.

Can you please tell me if it makes sense to try to disassemble the button? (And, if so, how?) Or am I wrongly sinning on her, and the problem may be something else?

In this topic, we will consider the malfunction of the screwdriver, get acquainted with how to check the screwdriver, and so on. An explanation will be given on personal photographs that will allow you to learn some of the details in checking the power tool circuit. Let's start with powering the screwdriver.

The battery of a screwdriver consists of individual electrochemical cells, which, unlike primary cells, are capable of restoring their chemical composition of the electrolyte during their recharging. How to repair a screwdriver battery if your screwdriver is out of order (broken). First of all, let's consider what the principle of obtaining electricity from such individual battery cells is based on. In the example, a manganese-zinc element is shown (Fig. 1).

A zinc vessel in such an electrochemical battery is a negatively charged electrode. A carbon rod is used as a positive electrode. The carbon rod is in the environment of an active material - manganese dioxide, as an electrolyte - a thickened solution of ammonia is used.

That is, the underlying principle is based on the use of reversible electrochemical systems. Substances of electrochemical batteries, formed during the discharge process, seem to return to their original state as a result of exposure to an electric current (in the process of recharging the battery). The screwdriver is powered by a battery - a group of electrically interconnected elements located in a common housing, as can be seen in the photograph (photo 1).

The screwdriver battery consists of individual elements. The electrical circuit of such elements can have a scheme of both parallel and serial connection (Fig. 2).

You can check the health of the cells after a certain time of their charging, that is, the presence of voltage on each cell, or the battery as a whole, is checked. If, when measuring the voltage of an element, the value on the display of the "multimeter" device will be a lower indicator (for example, not 1.2V, but 0.8V), then this element has lost its electrochemical properties during operation. Such elements must be replaced. Electrochemical cells for the battery (photo 2)

must be selected in accordance with their technical characteristics, that is, in terms of voltage and current. The indicator on the case of the removed battery cell, for example, is:

voltage: 1.2V;
current strength: 1200mA - 2900mA,

- therefore, it is necessary to select elements with just such indicators. Connecting elements to each other

performed with jumpers (photo 3). With this replacement, you will need a soldering iron, soldering tin and soldering acid.

This topic provides an example from my own practice.

So, in front of us in the photograph is a Bort screwdriver.

Initially, to find a malfunction of a screwdriver, you can check the total resistance of its electrical circuit.

Before checking, the start button must be turned on, that is, the button must be fixed, as shown in the photo (photo 4).

Then, using the Multimeter device, measure the resistance of the electric circuit of the screwdriver (photo 5).

To do this, the Multimeter device is installed in the resistance measurement range, then with the device probes we touch the removed contacts (on the handle) of the screwdriver, as shown in the photograph (photo 5), when measuring, the device display indicates a resistance that is not comparable for the operation of this power tool. The resistance value here is an indicator - a short circuit. According to the display of the device, it can be seen that this screwdriver is faulty.But we need to establish a specific cause - what is the malfunction?

To find the cause of the malfunction, it is necessary to disassemble the screwdriver and check the wiring diagram (photo 6).

In this electrical circuit, as we can see, the transistor consists.

The transistor is installed on a metal plate (photo 7), which serves to remove heat when heated. The transistor is checked for resistance between the junctions (emitter - collector - base). To check the transistor and not focus on the type of transistor (n-p-n, p-n-p), any two legs of the transistor are checked in both directions.

In this way, it was established that there is no conduction between the collector and the base of the transistor. But as a result of what could the transistor fail? We carry out diagnostics for individual electrical connections, namely, for the electric motor of the screwdriver (photo 8).

The photograph indicates an unacceptable resistance value for the electric motor (photo 8). What exactly is the reason for the malfunction of the electric motor? We look further.

The electric motor of the screwdriver is a DC collector motor. Graphite brushes are located on the end part of the electric motor cover (photo 9). The graphite brushes in this example are in good condition. Here you also need to check the conductivity of the contact connections (wire - brush).

The rotor of the electric motor consists of windings (photo 10), connected in series with each other. The stator of the electric motor is a permanent magnet with two poles, that is, the stator of the electric motor has no windings.

You can be convinced of this - metal objects are attracted by the electric motor housing (photo 11).

From this, we can conclude that in a malfunction of the electric motor, an insulation breakdown is observed between the wires of the rotor windings.

Well, here is the reason for the breakdown of the screwdriver, which consists in a malfunction:

transistor;
motor rotor windings.

All that remains is to replace the corresponding parts.

From this article, you will learn how to make an independent diagnosis of a malfunction of a cordless screwdriver

Any, even the most reliable electric tool, can fail during intensive use. However, this is not yet a reason to buy a new one. It is quite possible that the tool can be repaired. To do this, it is most convenient to contact the service center for help (especially if the instrument is under warranty), or to diagnose the malfunction and make repairs yourself.

For diagnostics and subsequent repair of the screwdriver, we need the following tools:

narrow flat-blade screwdriver;
Phillips screwdriver.

The reason for the repair was the unstable operation of the power button. When pressed fully, the screwdriver motor stopped working.

To diagnose a malfunction, it is necessary to disassemble the screwdriver body. To do this, remove the battery, use a flat screwdriver to remove the decorative cover on the case (under it are the screws for fastening the case). The pads are fixed on plastic fasteners, which break quite easily.

Using a Phillips screwdriver, unscrew the screws that secure the case (in our case, 8 screws) and carefully disassemble the case.

Upon opening it can be seen that the power transistor is melted. The transistor is involved in the smooth control circuit of the screwdriver speed. When the button is fully pressed, the motor power circuit is closed directly, allowing full power operation. Most likely the problem is in the button.

Make sure the engine is working properly. To do this, disconnect the two motor power wires from the button, pull them out and press with a narrow flat screwdriver on the spring contact of the button.

In order to get to the second wire, we take out the battery contacts and the button from the grooves in the screwdriver body.

We connect the screwdriver motor to the battery contacts (polarity is not important).Checking the rotation.

If the engine is in good working order, it is necessary to replace the button. It is important to choose a button specifically for a given screwdriver, since not all buttons can fit into the grooves in size. The button is sold complete with battery terminals and a transistor.

We connect a new button.

To do this, connect the motor to the button terminals. The polarity of the connection is not important at this stage.

We connect the battery contacts of the new button to the battery.

Press the button and check the direction of rotation of the motor. Pay attention to the position of the direction change lever. This is necessary in order to select the position of the rotation direction selection button that is familiar to you. If the position does not match, it is enough to swap two wires from the engine with each other.

We assemble the screwdriver body in reverse order. We thread the plastic pusher into its groove and connect it to the button lever. We install the battery contacts in the groove of the case.

We install the transistor with an aluminum plate in the groove.

We carefully place the wires in the case, taking into account all the slots and latches. This is necessary in order not to interrupt the wires during the reassembly process. The body should assemble easily and effortlessly.

We tighten the screws that secure the case with a little effort and install the plastic cover.

Video (click to play).

The new button fulfills all its functions: it provides smooth speed control, rotation direction changeover and full power operation. You can get to work!

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