Reason one: 0.3uF\/1200V resonant capacitor, 5uF\/400V filter capacitor damaged or insufficient capacity In the induction cooker, if the 0.3uF\/1200V resonant capacitor, 5uF\/400V filter capacitor smaller capacity, failure or good characteristics, will lead to the induction cooker LC oscillation circuit frequency is high, resulting in power tube IGBT tube damage. When other circuits are checked to be normal, we must replace the 0.3uF and 5uF capacitors together.
Reason 2: IGBT tube excitation circuit abnormal oscillation circuit output pulse signal can not directly control IGBT tube saturation, conduction and up, must be amplified by the excitation circuit to complete the pulse signal. If the excitation circuit fails.
Capacitor reduction voltage instability resulting in breakdown. This situation is generally the induction cooker power conversion chip burned out, it generally produces 18V voltage, and then 7805 into 5V voltage for the CPU to work, without 5V, the CPU does not work, the whole machine does not work. Induction cooker such chips are generally used viper12a, viper22a, thx203h and so on.
Test the periphery of the power conversion chip to see if there is a small device associated with damage, if there is, replace it.