Did you have checked the magnetron? If this appliance turn on, it is, you said "has power", but not generate microwaves to "cook" any meat you want to cook. I have searched more information on Internet, but not got something about it. If you have some like electric diagram give me the link please or up it to 4shared for try to help you to the solution. I beg your pardon for my poor english. Is not my natal language.
Design Considerations
The basic function and operation of the microwave oven since its invention in the mid 1940's has not changed much at all. Essentially the only major advances in this end equipment that have transpired over the years have been improvements in the user experience. Microcontrollers have helped in this regard as they include more features such as Popcorn, Dinner Plate and Defrost modes. Another rather recent innovation is the ability to measure the steam in the cooking chamber which provides the microcontroller information on cooking time required. As the internal microwave frequency in the magnetron is typically around 2.45 GHz and microwaves are almost as ubiquitous as washing machines, other wireless technologies such as Bluetooth which operate in the same frequency much have the capability to do frequency hopping in case of interference. Along with the traditional 5 V analog and logic commodity devices used in this end equipment, Texas Instruments also provides feature-rich products that integrate relay drivers, zero-volt detection, brown-out detect feature, and 5 V linear regulation that allow for keeping BoM (bill of materials) costs within budget.
5 V Logic and Analog: Texas Instruments provides the largest portfolio in the commodity space that gives designers the flexibility to choose from any logic function needed. Whether it's an AND gate or a single-bit buffer that is needed on the board, TI has it. Likewise, TI offers a wide selection of standard linear devices for regulation (linear regulators), LEDs (LED drivers), signal conditioning (operational amplifiers), etc and are available in industrial temperature range.
Integration: Texas Instruments provides fully-integrated solutions such as the digital signal controllers (for digital motor control, PFC, and other system functions), and relay drivers that provide up to 8 channels, zero-volt detection, and 5 V linear regulation. Aside from the commonly-used 7-bit relay drivers (such as the ULN2003A Darlington arrays) TI also provides the 8-bit TPL9201 or TPL9202 to drive LEDs on the display and triacs that may be used to operate the turntable. These devices also have integrated features that allow for the detection of the zero-volt crossing of the secondary side of the power transformer. Information is fed back to the microcontroller that lets it know when to switch ON/OFF the relays for better long-term reliability of the relays themselves. A brown-out detect feature that provides an early notification in case of a decrease in power supply voltage is available on the TPL9202. These devices also carry an on-chip 5 V linear regulator to power 5 V logic or microcontrollers that may reside on the board.