This Microwave key failure, not running, oven lamp does not light, not heat, each functional failure, was halted state, should be CPU working conditions failed.LG4service manual download site

Measuring the power of +5 V, +12 V power output is normal, CPU (3) pin voltage is about 4.6V normal; measuring clock oscillation pin (5), (6) feet voltage near ov, should normally were 2.8V, 0.6V ; measuring capacitance Cl, C3 serious' heavy leakage. Replacement of Cl, the C3, microwaves back to normal.LG4service manual download site