Light-emitting diode damage will also cause induction cooker does not boot
An induction cooker plug in the power plug after the display shines, press the boot key can not boot. Open induction cooker found on the back of the PCB board has a lot of oil, with alcohol after washing or not, only occasionally can boot, more time is not boot.
Considering the environment of the induction cooker is not very good, the key circuit should be placed first to check. Can check out all the keys, and did not find a button has a leakage of the situation. Later carefully observe the phenomenon of the machine, found that there is a light-emitting diode micro-light, which should be the key to show the leakage of the phenomenon, but the key is not leakage Ah!
So where does the voltage that causes light-emitting diodes come from? The cathode of the light-emitting diode is connected to the V, and the cathode is attached to the display and to the foot of the display-driven integrated block, at the same time as the key and another light-emitting diode. A light-emitting diode can emit light only if the negative voltage of the light-emitting diode is pulled down.
Measuring the resistance here, it is found that there is a resistance instability of the situation, finally found that the light-emitting diode is connected to the cathode of the other light-emitting diode leakage, and both positive and negative phenomena have occurred. It is because of this light-emitting two-level tube leakage, the CPU working conditions are abnormal (should be the same as the key leakage characteristics), so there is no power-on fault.
Most of the previous light-emitting diode damage was open circuit damage, I have not found a light emitting diode soft breakdown of the situation, you can think carefully, since the light-emitting diode is also a semiconductor, that appears and transistor and diode as the soft breakdown phenomenon is normal, but I have not met, it ignored.