DIY washing machine power supply repair

The power supply supplies 5 volts to the processor. Its transformer is located behind the input block. It is easy enough to get it for repair.

Since 2009, LG and Samsung machines began to be produced with the participation of Flextronics corporation. The power supplies of LG and Samsung washing machines use a step-down transformer with a primary winding of 230 volts and a secondary winding of 12 volts.

The principle of obtaining 5 volts from Samsung and LG machines:

• the second winding removes 12 volts AC;
• 12 volts DC are taken from the rectifier formed by the diode bridge;
• the secondary winding is grounded on both sides with two 33 k resistors;
• a diode is located at the end of the diode bridge; it does not participate in the voltage conversion process;
• there is a 2.2 mF capacitor in the RC circuit, the filter of this circuit reduces ripple;
• 12 volts are converted to 5 through the L7805 regulator;
• a filter with an electrolytic capacitor 470 uF completes the chain.

The 5 volt output powers the Samsung and LG washing machines.

The power supply unit, unfortunately, needs to be repaired or replaced more often than we would like. It must be checked first if the Samsung or LG washing machine refuses to turn on. We test:

They use switching power supplies. They are smaller compared to LG and Samsung PSUs. Despite the fact that they are usually produced on the basis of Flextronics, the circuit for Ariston and Indesit is fundamentally different.

Switching power supply for electronic modules of washing machines

The Indesit / Ariston machine has a varistor at the beginning of the circuit of such a block. Further, the voltage passes through capacitors, resistors, and a rectifier. After straightening, it is cut into pulses.

Visually, the fault will be on the board or inside the microassembly. These can be transistors, triacs or thyristors. Repairs may also require collision protection.

The study of the TNY 264 PN microcircuit, the main part of the pulse unit at Indesite / Ariston, will take a significant amount of time. The essence of her work is as follows:

• the first winding is grounded through the microcircuit;
• pulses are generated by a built-in switching power supply of 5.8 volts;
• secondary windings at the transformer 12 and 5 volts DC;
• BP output provides uninterrupted power supply to the built-in switching power supply;
• EN / UV pin enables input and monitors instability;
• S - for grounding internal semiconductors;
• HV RTN closes the voltage on the first winding.

Such a microcircuit is protected from overload, independently supplies impulses to the transformer and tests the outputs.

In the event of a malfunction of the impulse power supply unit of the Indesit / Ariston machine, a thorough study of all sections of the microcircuits will be required. It is advisable to find their descriptions. Power supply diagrams for washing machines are usually available on the websites of manufacturers or their service technical support, in our case Ariston and Indesit. Often, schematic diagrams of individual models can be found by manufacturer Flextronics.

Before dismantling individual parts of the washing machine, it will be useful to take a close-up photo so that later there are no questions about where these or those parts came from, and where to insert what.

Externally, the power supply can be identified by the supplied power and the transformer (or two). He disconnects. When working with the electronics of the washing machine, whenever possible, use anti-static accessories and clothing (gloves, wristbands, boots).

The washing machine does not turn on - there is no power.The question is why? Let's take a closer look at the washing machine today. Readers had time to check the outlet, the integrity of the cord, the water supply, read fortunes on the coffee grounds. Let's take people through the electronic jungle of washing machines. Let's talk about why the washing machine won't turn on. Finish checking the fuses (optional), let's go!

If the washing machine does not turn on, the power supply deserves the first suspicion. It is obliged to provide voltage supply (+5 volts) to the processor that lights the indication lights. Indeed, there may not be a switching power supply in the washing machine. There are few electronics here, the current consumption is low, and the transformer is of modest size. Would try to do it for the TV! Step-down transformer:

• Primary winding 230 VAC 50 Hz.
• Secondary winding 12 volts AC 50 Hz.

Moreover, 220 volts, 12 volts are effective values. Where to find a transformer? After the power cord, the input pads, which we agreed, are checked. The motor is powered through a line filter. The device does not protect the collector motor, on the contrary, it protects the neighbors: VCRs, disc players, home theaters, electronic units of the device. The filter is easy to check by measuring the output voltage. Should be 220 volts. How do I find a filter? The box following the block, the case outlines a schematic diagram composed of inductors, capacitors, resistors.

The detail was disassembled in detail by the forces of the portal. The diagram is drawn, copy for health, do not tell anyone and avoid getting water. The elements have a breakdown voltage of hundreds of volts. Consider when choosing an element base. The electronic unit of the washing machine requires power.

Samsung uses 5 volts, which are obtained in a typical way:

1. 12 volts of alternating voltage is removed from the secondary winding of the step-down transformer.
2. The diode bridge forms a full-wave rectifier from which constant 12 volts are removed.
3. For safety reasons, it is necessary to ground the secondary windings of transformers, done through two 33 k resistors - one on each edge (do not ask how it works).
4. At the output of the diode bridge, the next diode, we believe, is located here due to the retention of a larger breakdown voltage. From the point of view of signal conversion, the element does not play a role.
5. A parallel RC filter smooths out ripple. There is a 2200 uF electrolytic capacitor.
6. The familiar 7805 voltage regulator converts 12 volts to 5 volts.
7. The output was decorated with another RC filter, the capacity of the electrolytic capacitor is 470 μF.

A voltage of 5 volts is supplied to power the washing machine's electronic brain. The power supply is checked as follows:

1. It is necessary to check the voltage of the output of the secondary winding of the transformer. It is 12 volts (rms) under normal conditions. If not, the transformer is broken.
2. The input of the stabilizer is 12 volts DC. Otherwise, check the diode bridge (if the value is half as much), the 2200 uF capacitor.

Ariston washing machine power cable

They say there are no switching power supplies in the washing machine. Not true. Ariston / Indesit boasts a whole galaxy of products. The TNY 264 PN chip is operated by Italians. The global key in the form of a micro-assembly, in addition, compares the output voltages with the nominal values. The principle of operation is simple: when power appears, the pulse generator cuts the rectified mains voltage of 230 volts.

What is a switching power supply? It differs from the one discussed above in the size of the transformer. That, in the case of washing machines, does not so much help to reduce weight as it saves materials for the manufacturer, reduces the occupied volume. Major failures of switching power supplies are limited to component failure.

There is a protective varistor at the input.Check integrity. Then the harmonics of the input voltage are filtered using capacitors, inductors, and resistors. The rectifier is full-wave or half-wave (the current consumption is so low). One varistor protects the IC input against voltage surges by shorting to ground. The rectified voltage is cut into pulses. The greatest scope for technical solutions opens up. A careful study of the circuit will help to understand what is broken. The key will be transistors, thyristors, triacs. Geographically, it can be located on the board, or 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 (however, it is afraid of water), it costs about 60 rubles. Better than taking a new washing machine.

Chip. The documentation is freely available. The assembly is equipped with a built-in 5.8 volt power supply, a 132 kHz pulse generator. Power is taken from the Drain input (D). Let us 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 internal power of 5.8 volts is taken. The circuits of the impulse sources of the Indesit washing machines are obscure. We avoid giving the documentation, we will show a typical example of including a microcircuit from the company brochure for a product.

Around this mode, assembly is used in washing machines. There are two secondary windings of the transformer: 5 and 12 volts DC. Here is the purpose of the pins of the microcircuit:

1. Bypass (BP) is for grounding through a 0.1uF capacitor. Allows 5.8 volt internal power supply to operate.
2. Enable / under-Voltage (EN / UV). Contact has a dual function. Firstly, this is the permission of the operating mode, and secondly, the sensor for the minimum voltage. If 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 control the mode.

Washing machine repair

It turns out that the power switch on the MOS transistor is placed in the same case with the pulse generator. The circuit is different from typical power supplies. Inside protection against overload by overcurrent, also shutdown in case of overheating. It turns out a self-sufficient structure. Generates pulses for the transformer, along the way controls the output voltages.

Geographically, the power supply unit of the washing machine is located on the electronic board of the device. It can be determined by the presence of one or two transformers. As shown above, the power switch is sometimes integrated with a pulse generator, sometimes there is protection inside. Therefore, for structural division of the board, it is useful to find descriptions for all relevant microcircuits.

At times, the power supply unit is represented by a separate miniature PCB plate, in the manner of an expansion card for the motherboard of a personal computer, stuck into the slot perpendicular to the electronic brain of the washing machine. But the main thing is that the power bus should come to this place. 230 volts can go to various relays (sometimes located nearby) supplying the drain pump, inlet valve. As needed, the programmer (on-board computer, electronics unit - call it what you want) gives a signal to activate the selected equipment.

The electronic brain of the washing machine is connected to other components through connectors. Therefore, the module does not cost anything to undock. Be careful in the process. Disconnect with power off, avoiding static discharge. If possible, do not wear rubber shoes, sweaters, use special anti-static wristbands. It costs a penny (200 rubles), it will come in handy when repairing electronic equipment, but it will help to keep the most expensive component of the washing machine intact.

See, everything is as simple as two and two.We honestly hope that now readers 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 the official documentation for reference, like the one shown in the figure at the beginning of the article.

As it usually happens, a technician works at home for about 9 years, and then suddenly dies quietly. So it did not pass us by. The washing machine stopped turning on.
They did not call the masters, as it was already a sad experience, and even at the very hands it seems as if they were growing out of the shoulders.

I got into the typewriter. I unscrewed two screws from the back from the cover, removed it, disassembled the front panel, got to the control board, and the power supply board.

DC41-00060A power supply assembly with control board

On the power supply board, I immediately saw a swollen capacitor, well, in principle, the cause of the malfunction became clear. The capacity has dried up and instead of a constant voltage, we get a pulsating one, very few people will like this mode of operation.

It remains to find out what other components the capacitor dragged along.

Visible swollen capacitor 10μF 450V

Here you can see that everything was very hot

Having rummaged on the Internet, I found a similar case to mine. Not many screenshots.

Well, somewhere in the same place I found part of the power supply circuit

Samsung Power Supply Assembly DC41-00060A WF722S8R

And I began to saw and hack

Marked the autopsy area

I cut through the plastic with a stationery knife

Got access to component pins

Here I started to remove the sealant from the top side of the board.

I clean the section of the board from the sealant

Removed the sealant from the top of the board, gained access to the components

When the components were ringed, it turned out that the TNY266PN PWM controller also failed, it also dropped out

I put everything back in place, turned it on, and everything worked

Thanks to Eugene for consultations and support.

All modern washing machines are equipped with a control module. The more functionality the SM has, the more delicate the electronics: it is more susceptible to breakdowns, since it is sensitive to voltage surges in the network. Is it possible to repair the "brains" of washing machines with your own hands, how to diagnose their breakdown, we will find out in this article.

The main control box of the washing machine is equipped with two boards. One of them is responsible for the operation of all the details of the washing machine. The other provides the operation of the control panel - buttons, indicators - and has appropriate connectors for wiring.

Is the board not overload protected in any way? Of course, the manufacturer has provided a surge protector for such cases, which takes a hit during a power surge.

How to check the washing machine board and determine the breakdown?

The fact is that most of the signs can indicate a breakdown of both the module and other parts. For example, you notice that the machine stops working, the wash does not start. This may be due to a problem with the module or motor of the washing machine.

What may indicate a malfunction and subsequent repair of the board in the washing machine:

• СМА give an error code on the display.
• The system is "frozen" and does not respond to user manipulations.
• Washes for too long. The machine fills up and then drains the water, after which the system "freezes".
• The drum changes direction abruptly for no apparent reason.
• The spin mode does not turn on.
• The water overheats or does not heat up, which does not correspond to the selected mode.

However, the next time the washer is started, it may work as usual again.

Some models of the CMA have an autotest, which allows you to determine the cause of the breakdown. How to start it is written in the instruction manual of the machine.

1. A short circuit as a result of a voltage drop can lead to burnout of capacitors, thyristors, triggers and other elements on the board.
2. High humidity. If the SM is operated in a bathroom, over time, humidity affects the main unit, which leads to its malfunction.
3. Broken power wire. If the wire is cut abruptly, a power surge may occur, affecting the operation of the module.
4. Frequent abrupt unplugging of the machine over time may cause a malfunction.
5. Factory defects are less common.

Be careful when transporting SM from place to place. Be sure to pull out the powder dispenser as there is some water left in it. During transportation, water gets on the main unit, which leads to its combustion when connected.

To start repairs, you need a circuit board for the washing machine, as shown in the example of the Indesit washing machine.

We can advise you to superficially inspect the module to find burnouts and damage. There are other ways to check, but they can only be carried out by an experienced specialist. If faults are identified, you will have to replace the "brains" for the washing machine.

To carry out a visual inspection, we will figure out how to remove the washing machine board. First unplug the washing machine, then proceed as follows:

• Pull out the detergent dispenser drawer. To do this, pull it towards you while pressing the latch in the center.
• Now remove all screws holding the control panel.

• Use a screwdriver to release the plastic clips. Remove the panel from the case.

• The main unit is located behind the panel. Take a photo or mark the location of the wires with a marker. Then disconnect them and remove the unit.
• You may need to release the block latches to get to the board.

Once the board is in front of you, carefully examine it. Did you notice some burnt areas? Then you need to repair the control unit of the washing machine.

We will show you how you can replace some of the elements. To do this, you will need a soldering iron and a new part.

• Capacitor. On the control board, it serves as a kind of stabilizer. To replace it, you need to solder the new part to the positive electrode. Use a tester to find out where which electrode is.

• Resistor. A tester is used to check the operation of the resistor. 1st order resistors should show a result of 8 ohms and an overload of 2A. Second-order resistors show 3-5A, while the resistance indicators depend on the frequency of the module. If the indicators do not correspond to the norm, the elements are replaced by soldering.
• Thyristor block. You can check the thyristor unit by measuring the negative resistance. Indicators should be no higher than 20V. The filter of the block could also burn out. You can repair it by cleaning the cathode.
• Trigger. The trigger test is to measure the voltage of the input contacts. Their readings should not exceed 12 V. The resistance of the trigger filter should be 20 ohms. Replacement of the element is also carried out by soldering.

The soldering of the board components can be disturbed by strong vibrations from the machine. Therefore, you need to monitor the correct and stable installation of the washing machine.

The master knows how to properly repair the control board. Think before starting your own repair, because the electronic unit is quite expensive. If you do not have the skills to work with a soldering iron, and the verification indicators do not give specific results, contact the service center.

For those who nevertheless decided on an independent repair, a video on the topic:

Modern washing machines are reliable and functional. The manufacturer does everything to ensure that his product works for many years without interference. However, the washing machine control module fails more often than the owners of the unit would like. This happens for a number of reasons, some of which are separately negotiated by the manufacturer, and non-compliance with the conditions set by him leads to the termination of warranty obligations. Others may be caused by marriage. However, if the warranty period has expired, you can try to make an independent repair of the washing machine control board or carry out detailed diagnostics.

The control module is the computerized heart of the car.Depending on the incoming signals from sensors and regulators, the control board activates one or another functionality. It is quite versatile. The manufacturer puts the same part on different brands of washers, labeling them differently. For example, the most common models of the electronic module of the Indesit washing machine are marked as W105TX, WISL82. Depending on the generation of a particular washing machine model, the firmware of the central processor or the number of input and output signals may differ.

• monitors temperature;
• sets the mode in which the electric motor operates;
• counts the time segments of the programs;
• responsible for starting the drain pumps;
• provides control of the inlet water pressure and the functioning of the feed shutter;
• is responsible for blocking operation.