Overhaul to the high voltage transformer T is bounded, were examined on the left and right of the high voltage circuit voltage circuits showed no abnormalities, estimated the problem lies in the computer control panel, and its related partial circuit diagram shown below (components digit number is the original circuit board Note ). The second door interlock switch S2 pin is shorted to ground, connected to the mains, delete microprocessor IC01 (TMP47C400RN-FD31) power supply terminal (42) feet voltage 5v; reset terminal (31) feet low, indicating that power, reset circuit is normal. Judging from the fault lies in the clock oscillation circuit. IC01 measured with a digital multimeter oscillation signal input terminal (31) feet, the oscillation signal output terminal (32), respectively pin voltage 0.6V, 0.32V. Normal voltage is 2.62V, 2.36V. Description (31), (33) pin voltage is not normal, then check C8, C9 were normal. Thus confirmed that the internal crystal osc bad or damaged, causing abnormal oscillation frequency, resulting IC01 internal circuit does not work that caused the failure. After replacing the OSC (4.19MHz), power test machine, microwave oven is working properly, troubleshooting.Saiservice manual download site