If multicooker not turning on this article may help you. We will tell you about how to repair a multicooker with your own hands and reduce the cost of this process.
The device and principle of operation of the multicooker
Before talking about how to troubleshoot multicookers, you should know that all home multicooker programs are trade secrets of manufacturers. Multicookers are based on the installation of two sensors, thanks to which they understand what is required of them. Many craftsmen suggested that the board contained a memory of the temperature and duration of individual operations and specified programs. Thanks to these data, the heating element (heating element) is being programmed. Sensors installed in the multicooker:
- Thermistor. It is installed on the main button of the device. Its dismantling is a rather painstaking task, for the reason that manufacturers categorically oppose repairs by self-taught and workshops, leaving it only to warranty services. Company Redmond went even further, they filled all the terminals with a compound, making it impossible to dismantle the removable terminals.
- The second sensor is installed inside the cover. To gain access to it, you need to make a lot of effort, so we do not recommend that you take it on if you are not confident in your abilities. It is necessary to remove the required connector without paying attention to the compound, and then start the multicooker. If after turning on the multicooker does not work, then you have found the cause of the breakdown. In order to be 100% sure of this, it is necessary to measure the resistance of the sensor coming from the wires and the cover using a multimeter. In Redmond devices, cables are located in the loop area under a removable cover. In order to take measurements, you need to unscrew the screw, then carefully remove the shield and remove the wiring from it, then turn on the multicooker while measuring the resistance.
As follows from the above, for proper operation, the multicooker needs to take readings from two sensors. They transmit their signal to the control terminal of the board via two wires. As a rule, the board itself is installed under the button panel. The next possible problem could be the power supply. In order to make sure that it is working properly, you need to connect the multicooker to the mains, if at least one of the indicators lights up, it follows that everything is in order with your power supply. Otherwise, it must be replaced.
Multicooker control is divided into mechanical and touch. If mechanical control is installed in the multicooker, then microswitches are built into the printed circuit board. By counting the number of “closures”, the microcircuit selects related parameters for performing operations. All this functions thanks to just one wiring. The beginning of the process of program execution is carried out by means of transmission of only one signal. However, for this it is necessary to use a large number of functioning control boards installed in the multicooker. The signal is constant and is needed to turn the transistor on or off. Thanks to the voltage stabilizer, oversaturation cannot occur on the contact fields.
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Switching power supply
Let’s talk in detail about how exactly it is arranged. Its design includes a transformer, pre-wound with electrical tape, so that the contact does not fall off, it is occasionally filled with a compound. In order to protect the transformer from input ripples, an input filter is provided in the design. The multicooker itself does not create pulsations. The transformer provides for the installation of two windings in parallel connection. The use of two windings increases the reliability of the device.
If Multicooker won’t turn on it is necessary to measure the resistance of the transformer, it is not necessary to disassemble the device, since the relay is open in the disassembled state. The resistance between the plug and the input terminals must be low. The transformer is followed by a two-period rectifier of four diodes. After it, an additional filter is provided in the power supply from the largest resistor with a capacitor. Next, an emitter follower with a stabilizer and a resistor is installed, which is designed to select the operating point.
Be sure to pay attention to the small gap of the double wire, which is located in the area of the fuse. This part of the design is responsible for supplying 220V current to the device, connecting to the relay. The main board is installed in the device with the elements down, if the current exceeds the limit value, the copper wire will simply melt and drain to the bottom of the unit, which is completely unprotected from this. If, when removing the main board, you notice this kurtosis, then this means that a short circuit has occurred somewhere inside the device. These damages may indicate the loss of performance of the heating element of the multicooker. But do not immediately take on the restoration of the jumper.
When measuring the resistance of a heating element, its operating value fluctuates around 30 ohms.
To check the operation of the relay, you must connect the device to the mains and turn on any of the pre-installed programs on the multicooker. If a click occurs while the device is turned on, then this is a signal that everything is in order, otherwise it is necessary to gradually replace the relay and control circuit. In order to diagnose a malfunction of the latter, it is necessary to apply voltage to the middle terminal (transistor) along the white wire. Then measure the output voltage. However, it is worth noting that manufacturers like to fill everything with a compound, so be careful.
Consider cases of thermal fuse failure
What is a thermal fuse? This is a small cylindrical piece of wire, which in its external shape may remind you of a resistor. The operating temperature of the device is 170 ° Celsius, and the current ranges from 10 to 15 amperes, depending on the installed element. If one of the parameters exceeds the norm, the thermal fuse will burn out, which breaks the electrical circuit and stops the operation of the device.
You could set out to make such a fuse yourself. First of all, it is not worth denying that these products are easy to manufacture, but it follows from this that the price for them will be quite low. Secondly, it is desirable to install exactly the original elements. A factory copy has certain fixed characteristics, calculated in production from the very beginning, and a copy made by oneself may have different characteristics from it, which can lead to bad consequences. In the worst case, using a homemade part can end up in a fire for you.
Thermal fuse replacement process
Getting to the location of this part is not too difficult, first you need to remove the saucepan from the cavity of the device. Under it you will find a metal element similar to a mushroom, the “leg” of which is attracted by a spring. Under it are thermal fuses, usually they are installed in several pieces and covered with cambric.
Cambric is a plastic conductive insulation element, in most cases white, used to protect the junctions of various components and areas.
In order to attach the element, it is necessary to perform firing. The use of a soldering iron for these purposes is strictly prohibited. The heating element of the soldering iron will burn through the heat-sensitive element without much effort and difficulty.
To determine the integrity and performance of one or more elements, you must use a multimeter. It is not necessary to remove the part, after detecting a malfunction, eliminate it according to the above example.
A little about Redmond
Multicooker Redmond It also has thermal fuses that protect the device from overheating. These parts do an excellent job with the function assigned to them, but there is one very significant BUT — they are able to do this only once. After that, you will have to seek the help of a specialist in a service center. Here is an extract from the Redmond warranty card: “a product with thermal and other damage caused by improper operation of the device is not a warranty case.” Since it is not uncommon for owners to turn on devices without a saucepan, this is quite important to know. However, a button is installed in the device, which, in theory, should prevent the device from turning on without it, but it simply does not work at Redmond.
If, by negligence or forgetfulness, you did not set the saucepan in place and poured the ingredients into it, poured the required amount of liquid and forgot to unplug the device, and then remove all moisture and food with paper towels, but the device stopped working, according to the manufacturers, the fault will be lie on you. This is justified by the fact that the guarantee does not apply to getting these things into the cavity of the device, and you will have to pay for expensive repairs out of your own pocket.
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In typical models, two electronic boards are installed:
- Control fee.
- Power board.
The second is located on the bottom of the device, but to get to the location of the first item, you will have to suffer a little and completely disassemble the device, while dismantling the inner cylindrical surface.
After you have taken everything apart, you need to examine the boards for the presence of:
- blackened resistors;
- violation of solder seams;
- swollen capacitors;
- and soot.
In case of detection of such defects, it is necessary to replace the elements with new ones. Restoring broken soldering should not cause you much difficulty. It is necessary to carry out the process of restoring the tracks by cleaning them by tinning damage and zero sanding. You may need to add some jumpers, which you can make from the legs of the resistors. After performing all operations, it is necessary to cover everything with varnish to ensure the protection of the device from leakage and exposure to oxygen.
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If you have Multicooker won’t turn on do not immediately headlong to carry it to the service. All breakdowns are most often due to improper operation of the device. In the case when you properly operate the device, it can work for many years and make your life easier. In order to fix all the problems, you must follow the above instructions and with common sense, you can easily fix the multicooker. However, remember that if your device is under warranty, it is best to contact a service center.