Judging from the phenomenon should be serious short circuit caused by input mains insurance tube circuit circuit. Open shell, observe the magnetron (type 2 m211a - M1), high voltage rectifier diode (model HVM12), high-pressure two-way protection on opposite sides of the high voltage capacitor diode, models of 2 x062h, the bidirectional diode are identified as two cathode relative diode symbol one large and one small, big for Dl, small for D2 (D) 7 kV reverse pressure, reverse voltage of 1.7 kV), D2 mains input insurance tube (250 v / 8 a) serious burn out. Uk8service manual download site
 Uk8service manual download site
Measuring high voltage capacitor after two pin no voltage, first a magnetron filament pins and high voltage capacitor anode from the pins unplug (suspended), in a 250 v / 10 a insurance tube after charging, the panel LCD display, key operation have response, explain the control circuit is normal. The fault may be located in the high voltage circuit. Blackouts, measuring about 0.4 Ω magnetron filament resistance, not break: test the high voltage transformer the primary resistance about two Ω (filament winding supply not open). The high voltage winding of resistance is about 147 Ω, shows that high voltage transformer the basic normal: magnetron filament resistance to ground up, magnetron cathode and anode not short circuit; U F high-voltage capacitance measurement is 1, normal; Disconnect high-voltage rectifier diode grounding end. Stop the forward resistance can be measured with a pointer multimeter l0k electricity is about 150 k Ω, reverse resistance up to normal: remove the high pressure two-way protection diode, positive and negative to the resistance are 0 Ω measured show that the element is punctured short circuit. Replacement model with high pressure two-way protection diode (note that the direction of the pipe, pin, big diode symbol on the edge of the pin should be connected to magnetron filament), restore the unplug all pins, clean and asbestos board inside the furnace, charging, the respectively with three microwave heating of commissioning, including work, troubleshooting.

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