Most often the high-voltage diode fails, the magnetron fails less often. Not on the last place mica laying. At repair check existence of supply voltage of the magnetron-2500 - 3500 To the magnetron are come by 2 power wires for giving of tension on ( and heat.
External survey check also quality of electric installation: reveal integrity of connecting conductors, lack of zatek of solder which can lead to short circuits between separate sites of the scheme, find wires with the broken isolation, check quality of the soldering, and also existence of all elements according to the scheme. External survey control compliance of face values of components, reveal defects of separate elements (break of conclusions, a carbonization of a surface of resistors, mechanical damages of ceramic condensers, etc.).
External survey is made, as a rule, at powered off. Thus it is necessary to watch that casual subjects which at turning on of the device can cause short circuit did not get to installation.
Way of replacement of separate faulty elements, knots or blocks on serviceable widely use during the checking and repair. For example, having replaced the block, the module on obviously serviceable, it is possible to be convinced of malfunction of the replaced.
Simple method of check of the transformer or magnetron. It is necessary to remove the plug from the magnetron, to take it aside that did not punch a high voltage, then to turn on the furnace in an operating mode for some seconds, to switch off it and at once to dress the plug back on the magnetron. If the small spark slips, the transformer and high-voltage elements are usually serviceable. In case the furnace does not heat at the serviceable transformer and the checked safety lock the magnetron is faulty most likely.