A screwdriver is a very useful tool in the household. Perhaps not to list all the situations when it can come in handy, this is the assembly of furniture, and screwing shelves and fastening cabinets and much more. The work of twisting the screws, which our fathers did 20 years ago long and tediously by hand, with the help of a screwdriver, is done in a matter of minutes. Therefore, the failure of the screwdriver at the right time is very unsettling. Faults, of course, can be different, but we will talk about one of the most popular. charging does not charge our tool. Let’s see how to be in this case and whether it is possible to repair the charger of a screwdriver yourself.
The manifestations of this type of malfunction can be quite diverse. For example, charging in principle does not charge our instrument. Or it charges, but it discharges too quickly. And sometimes the charger can not fully charge the screwdriver. We will consider these situations.
The main malfunctions and how to solve them
So, you have a great screwdriver. You actively use it, but at one not-so-wonderful moment, the battery starts to discharge very quickly. The reason for this most often lies either in the general deterioration of our battery, or in the charger, which is faulty and charges it poorly. If everything is clear with the first case. there is no need to replace the battery, then with the second we will try to figure it out. over, it is better to understand immediately in practice, so we will take a specific charger and we will "treat" it.
In our case, this is Bosch charging, which works with a nickel-cadmium battery.
For those who are very concerned about issues of originality, we immediately explain that it was made in China, but at the same time it was factory-made and manufactured in compliance with all necessary standards.
At the connector, we can see three contacts, two of which are power, and one is the control.
Most often, we are faced with the case when the battery is charging, but the charge does not go, although the battery is not charged.
In any case, the problem can be solved only by disassembling our device. To do this, untwist the mounting screws and carefully remove the housing cover. Our charger is divided into two parts, in one of them there is a place for an AC current transformer, in the other for a rectifier. There are power connectors and a control chip, as you can see in our illustration.
Video: Battery Charged But Screwdriver Doesn’t Work
To check our charger, you need to plug it into a power outlet and replace the voltage indicator. If voltage is present, then most likely you will need repairs associated with the contacts of the device.
The work is quite laborious, but quite real. As we said above, in the charger there are power contacts, there are two of them, and a control contact. We have to check them, and all three. This will require some preparatory work. Our task is to take voltage measurements at the terminals of each contact at the moment when the charge is on. To do this, we need a tool. Soldering iron and thin wires. These wires need to be soldered to the contacts, they will help us measure the voltage indicators when the charger is working.
To avoid confusion, we recommend choosing different wire colors for plus and minus.
After carrying out these preparatory work, you can begin to test the charge. To do this, we measure the voltage value with a multimeter with the moment when an electric charge is applied to the terminals.
What do we see from the measurement results? If the voltage “jumps” and does not show stable values, then this is an indicator that this is where the cause of the malfunction is. In this case, it also happens that with the slightest movement the voltage disappears altogether. Most likely, this problem is connected with the contact terminals being bent, which means that the contact is loose and does not provide the stable voltage necessary for normal charging of our device.
A malfunction of the control contact affects the charging quality especially, since it is he who is responsible for supplying the normal voltage to the terminals.
The instability of the contacts violates the logic of charging the device. What can we do in this case? We cannot close the contact. This is due to the fact that the battery includes, as an integral part, a thermistor device that changes the resistance value in response to a change in temperature in the battery. This means that it acts as a protective device that protects the battery from being overheated or overcharged.
Knowing this feature of the battery, we should take the following actions. First of all, you need to bend the terminals. And then during the charging period you need to monitor the voltage with a multimeter. We will see that first there is an increase in its value, and then a decrease. And of course, you should pay attention to the charge indicator lamp on the device itself, it signals whether charging is in progress.
When measuring voltage, it is very important to pay attention to how fast it grows. If the speed is high enough, then this indicates the working condition of the battery. But if the voltage rises at a very low rate, then this indicates battery wear. You should pay attention to this signal and replace the battery. So, as you can see, we also need a voltage growth indicator to assess the degree of battery wear.
As a rule, after carrying out the above manipulations, the charger works fine. Only you may still need additional fixing of the charging socket, this can be done using electrical tape.
As you can see, repairing the charger of a screwdriver with your own hands is a rather painstaking, but quite real process. So do not rush to throw out the faulty charge, but try to figure out the causes of the breakdown and eliminate them. And your "shurik" will again serve faithfully!