According to the symptom analysis may be high voltage power supply circuit caused by a short circuit or overloading. Overhaul to the high voltage transformer T1 primary for the sector (see figure), first unplug the connectors at both ends of the primary T1 XT1 and XT2, so T1 primary and front-end circuit is disconnected, then connect the power, the operation start button, microwave "cuckoo" sound eliminated, thereby confirming the basic front-end circuit to work properly, the fault lies in the high voltage circuit. Power, for safety reasons, first with an insulated screwdriver to discharge the high voltage capacitor C short circuit detection C, R, VD2, VD1 and MT were normal. Re-testing of the primary winding of T1, filament winding and high voltage winding, found high voltage winding DC resistance than normal resistance decreases 3Ω (formerly 116Ω, measured with a digital multimeter), thereby confirming the high voltage winding inter-turn short-circuit breakdown, resulting in high pressure power overload, the core vibration caused by the failure. After replacing the high-voltage transformer with model specifications, power test machine, troubleshooting.Y7zservice manual download site