The washing machine does not turn on - no power. The question is why? Let's discuss deeper the washing machine today. Readers managed to check the outlet, the integrity of the cord, the flow of water, read the tea leaves. We will carry people through the electronic jungle of washing machines. Let's talk why the washing machine does not turn on. Stop checking fuses( optional), go!
The device of washing machines in terms of power
If the washing machine does not turn on, the first suspicion deserved the power supply. It is obliged to provide a voltage supply( +5 volts) to the processor that lights the indication lights. Indeed, the pulse power supply in the washing machine may not be. There is little electronics, the current consumption is low, the transformer is of modest size. Would try to do for tv! Step-down transformer:
- The primary winding is 230 volts AC 50 Hz.
- Secondary winding 12 volts AC 50 Hz.
Moreover, 220 volts, 12 volts are effective values. Where to look for a transformer? After the power cord, the input pads, which, we agreed, are checked. The engine is powered through a surge protector. The device protects a non-collector motor; on the contrary, it protects its neighbors: video recorders, disc players, home theaters, apparatus electronics units. The serviceability of the filter is easy to check by measuring the output voltage. Must be 220 volts. How to find a filter? The box going to follow the block, the case describes the schematic diagram, composed of inductors, capacitors, resistors.
Detail disassembled in detail by the portal. The scheme is drawn, copy to health, do not tell anyone, and avoid water. Elements have breakdown voltages of hundreds of volts. Take into account, choosing the element base. The electronic unit of the washing machine requires power. Samsung's
uses 5 volts, which are obtained in a typical manner:
- 12 volts of alternating voltage are removed from the secondary winding of a step-down transformer.
- The diode bridge forms a full-wave rectifier from which 12 volts are removed.
- Due to safety measures, it is necessary to ground the secondary windings of transformers, made through two 33k resistors - one for each edge( do not ask how it works).
- At the output of the diode bridge, the next diode, we believe, is here due to the holding of higher breakdown voltage. From the point of view of signal conversion, the element does not matter.
- A parallel RC-chain filter smoothes pulsations. Here is an electrolytic capacitor of 2200 microfarad.
- The familiar 7805 voltage regulator converts 12 volts into 5 volts.
- The output is decorated with the next RC-filter, the capacitance of the electrolytic capacitor is 470 microfarads.
A voltage of 5 volts is supplied to power the electronic brain of the washing machine. The power supply is checked as follows:
- The voltage of the secondary output of the transformer should be checked. Under normal conditions, it is 12 volts( rms value).If not, the transformer is broken.
- At the input of the stabilizer 12 volts DC.Otherwise, check the diode bridge( if the value is half as much), the capacitor with a capacity of 2200 microfarads.
- At the output of the stabilizer exactly 5 volts DC.Otherwise, the chip is defective 7805, check the resistance, the capacitor 470 microfarads.
Switching power supplies of washing machines
They say that there are no pulse power supplies in the washing machine. Not true. Ariston / Indesit boasts a whole pleiad of products. The TNY 264 PN is operated by the Italians. The global key in the form of a microassembly, in addition, compares the output voltages with the nominal values. The principle of operation is simple: when a power source appears, the pulse generator cuts the rectified voltage of the 230-volt network.
What is a switching power supply? It differs from the transformer size considered above. That, in the case of washing machines, it is not so much helping to reduce weight as it saves materials to the manufacturer, it reduces the occupied volume. Major failures of the switching power supplies are limited to component failures.
At the entrance there is a protective varistor. Check integrity. Then the harmonics of the input voltage are filtered using capacitors, inductors, resistors. A half-wave rectifier or a half-wave rectifier( the current consumption is so low).One varistor protects the input of the chip against power surges, shorting it to ground. Rectified voltage is cut by pulses. The greatest scope for technical solutions. To understand what is broken, a careful study of the scheme will help. The key will serve transistors, thyristors, triacs. Geographically, it can be located on the board, or it can be part of a microassembly.
To understand why the washing machine does not turn on, you will have to study the documentation. TNY 264 PN has protection against collisions( but is afraid of water), costs about 60 rubles. Better than taking a new washing machine.
Chip. Documentation is freely available. The assembly is equipped with a built-in power source of 5.8 volts, a pulse generator with a frequency of 132 kHz. Power is taken from the Drain input( D).We will explain. The primary winding is grounded through a microcircuit, the process is controlled by an internal pulse generator, and cutting is immediately obtained. From this potential, the power of the internal 5.8 volts is taken. Schemes of pulse sources washing machines Indesit obscure. We avoid citing documentation, we will show a typical example of switching on a microcircuit from the company's product brochure.
Approximately in this mode assembly is used in washing machines. The secondary windings of the transformer are two: 5 and 12 volts DC.We give the purpose of the conclusions of the microcircuit:
- Bypass( BP) is designed for grounding through a capacitor of 0.1 microfarad. Allows you to operate an internal power source of 5.8 volts.
- Enable / under-Voltage( EN / UV).Contact has a dual function. First, it is the resolution of the operating mode, and secondly, the sensor for the minimum voltage. If the feedback approaches the DC line through a resistor, the mode is corrected in the desired direction. In the absence of a resistor, the microcircuit is able to determine the situation, does not perform control over the mode.
- Source( S) ground wire internal MOS-structures.
- Source( HV RTN) is grounded, used to close the current through the primary winding.
It turns out that the power switch on the MOS transistor is placed in the same package with the pulse generator. The circuit differs from typical power supplies. Inside protection against overcurrent overcurrent, also shutdown when overheating. It turns out self-contained design. Produces pulses for a transformer, simultaneously controls the output voltage.
We repair the power supply unit of the washing machine
The power supply unit of the washing machine is located on the electronic board of the device. You can determine by the presence of one or two transformers. As shown above, the power switch is sometimes integrated with a pulse generator, sometimes with protection inside. Therefore, for the structural division of the board, it is useful to find descriptions for all relevant microcircuits.
At times, the power supply is represented by a separate miniature PCB plate, in the manner of an expansion card of a motherboard of a personal computer inserted into a slot perpendicular to the electronic brain of a washing machine. But the main thing is precisely in this place the power supply bus should come.230 volts can be sent to various relays( sometimes located nearby) feeding the drain pump, inlet valve. As needed, the programmer( on-board computer, electronics unit - call it what you want) sends a signal, use the selected equipment.
The electronic brain of a washing machine is connected to other components via connectors. Therefore, the module does not cost anything undocked. Be careful in the process. Disconnect with power off, avoiding static discharge. If possible, do not wear rubber shoes, sweaters, use special antistatic wristbands. It is worth a penny( 200 rubles), useful for repairing electronic equipment, but it will help to preserve the integrity of the most expensive component of the washing machine.
See, it's as simple as two and two. Frankly hope that readers now know how to fix a washing machine. By the way, do not trust the schemes from the network of various domestic craftsmen too much; use official documentation for reference, like the picture presented at the beginning of the article.