My oven is working but the item inside is not heating. If I put 2 minutes, the oven wprks for 2 minutes, but the item inside is as it is without slight heating
It's very likely the high voltage fuse has blown, often because there's a fault in the cook section, or the fuse has metal fatigue. It will be in a thick plastic tube near the transformer and cook capacitor. Turn the oven off and unplug it for 10 mins, then take the cover off. As a precaution, short out the cook capacitor with a screwdriver. The capacitor is near the transformer, usually an oval shaped can. If it's not fuse fatigue, it can be: faulty capacitor (unlikely); faulty protection diode across capacitor, if there is one (very likely, must be replaced same way round as original); faulty rectifier diode from capacitor to chassis (less likely) or a magnetron heater that is leaky to chassis. All these things need to be disconnected, and tested one by one with a 500V insulation tester, because an ohmmeter will often not show faults in high voltage parts. Any leakage at 2200V will blow a fuse. If there's no high voltage fuse, it will blow the mains fuse inside, then nothing will work, but it's not that with yours, since it partly works. The oven can run without the high voltage fuse, just replace it with a wire with nice thick insulation, or with some plastic tubing over it. Anything else that's faulty must be replaced. I get my parts from WES Components at Ashfield in Sydney. Microwave parts in the cook section have high voltage ratings, and must be replaced with at least equal rating components. I just fixed a Samsung microwave with its high voltage cook fuse blown. The rest was ok, so I'd say the fuse wire inside had metal fatigue. I also always put a drop of light oil on both ends of the fan shaft, it runs quieter and faster then.
If the fault happened suddenly, it will be one of the above faults. If the oven is very old, it will have a gradually increasing cook time, as the magnetron wears out. If the cooking time is too long, replace the magnetron, they're only held in with 4 screws or nuts. It must be the same physical fit and at least the same power rating as the oven's rated output power.
