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There’s no time to cook on a weekday morning. Many people start the day with a cup of coffee and a snack heated in the microwave. However, household appliances sometimes fail at the wrong time. Let’s figure out what to do if the microwave oven doesn’t want to heat up, and how to deal with the problem.  

Why does the microwave not heat: the main causes of the malfunction

  The reasons can be divided into 2 groups:   Problems whose solution does not require the use of a multimeter and a soldering iron: not enough voltage in the electrical network, poor ventilation, set the wrong mode, etc.   Problems that require “looking under the hood”: a magnetron, fuse, diode, or capacitor has failed.  

Problems with the voltage or overload of the network

  Microwave ovens are not particularly whimsical, but they do react to voltage problems. The microwave will not heat well if:   – There is not enough voltage in the power supply. In theory, the power supply organization should supply 220 V. However, unfortunately, in small towns, many consumers are forced to settle for 160-200 V. This voltage is only enough to heat a plate, the dish itself will remain cold. To remedy the situation, try setting the mode to a more powerful one and/or give the appliance more time. A radical way to solve the problem is to install a voltage regulator.   – The user can cause an overload by connecting two powerful appliances to the same outlet. To remedy the situation, leave only the microwave on. You may be able to reheat the food afterwards.  

Door malfunction

  A properly functioning microwave oven will not operate with the door open. When you close it, the contact closes, and the appliance is ready to heat food. The operation of the mechanism can be seen after removing the housing cover. The latch on the door can break during a move.   To prevent this from happening, transport the appliance in a box, using seals when packing. You can also fix the door with tape. If the door does break, the microwave will most likely not spin the tray at all, but there may be heating problems. Troubleshooting options include replacing the latch or the door.  

The ventilation system is blocked

  In this case, the heat will initially come out, but after a while the microwave will stop heating. Air circulation must be ensured for the device to work. Without it, the components overheat and the appliance turns off. This is how the safety mechanism prevents malfunctions. To bring the microwave back to life, wait until it has cooled down, remove any obstacles to cooling, and then turn it back on.   Follow the instructions for installing the microwave oven. Do not place the appliance against a wall. It is also not recommended to place various large and small gadgets, laptops, etc. on top of it.  

Magnetron malfunction

  To check the magnetron, first of all, we ring it with a multimeter. Before the procedure, disconnect the transformer part. Check it in 2 stages:  
  1. Connect the probes of the multimeter to the free contacts. If it does not respond, this indicates a malfunction. A characteristic squeak or other sign should give you hope.
  1. Connect one probe to any terminal, the other to the magnetron body. In this position, there should be no squeaking, the opposite indicates a breakdown of the output capacitors. They can be soldered out and replaced with new ones.
  Removing the magnetron can help with the diagnosis. It is enough to unscrew 2-4 screws. Remove the cap with your hands, without pliers, and see if there is a breakdown under it. If there is, the magnetron will have to be replaced with a new one. If only the cap is burnt out, we look for a replacement for this small part.  

Fuse failure

  Microwave ovens differ markedly in design, but in any case, there are 2-3 fuses in the case: the first is on the network board, the second is near the capacitor, and the third is on the control panel. If the first one blows, the appliance will not turn on at all, we need the second fuse.   We ring it by connecting probes before and after the part. The multimeter beeping is a good sign. Otherwise, you need to replace the fuse with an analog of the same rating. However, this is sometimes not enough: the microwave oven can work, but not heat, if the magnetron has failed along with this part.  

Capacitor failure

  A capacitor is a part that can accumulate electric current. Again, we use a multimeter to check its performance. Set it to ohms, for example, 200 ohms. Connect the probes to the terminals. The polarity does not matter. A good capacitor will gradually produce a few volts. If the value appears immediately or the multimeter remains at zero, this indicates a malfunction.   Next step:   – Switch the tester to the diode test mode. – Attach one probe to any terminal and the other to the capacitor case. A squeak is an indication of a breakdown.  

High voltage diode malfunction

  This part is located next to the capacitor. In some cases, you can tell if it is faulty by its appearance. In case of problems with the diode, the microwave sometimes makes a buzzing noise, and when it overheats, you can smell burning. In the absence of overheating, it will not be possible to confirm the diagnosis after a visual inspection. There is still the option of testing. To do this, you need a 9-volt battery of the “Crown” size. Set the multimeter to direct current and connect the battery through the diode. Then repeat the procedure after turning the diode over. If the diode is in good condition, then in one case the multimeter will show something like 1 volt, maybe more, and in the other nothing at all.   A diode malfunction can be attributed to non-obvious problems; in case of problems with it, it is sometimes difficult to understand why the microwave oven does not heat. However, after testing, everything is clear.   Parts whose inadequate operation may be accompanied by a buzzing sound also include a transformer.  

Other causes

  Sometimes the reason is inattention. Users sometimes forget to set adequate power before switching it on, and as a result, the microwave oven does not really heat up.   Problems with the mica plate located in the microwave oven cavity are also easily resolved. The dielectric material protects the magnetron from high temperatures. At the first sign of a malfunction, the plate must be replaced, otherwise, you will have to fix more serious problems later.   It’s time to call for professional appliance repair in San Diego county. San Diego Appliance Repair Service is here to help with professional and experienced appliance repairs.   Contact us   (619) 719-5005   [email protected]