The electric cooker hasn't been boiled for four hours.

1, your voltage is not enough, or the plug connection is poor. Check voltage and plug connection. If you don't have a multimeter, you can also plug the rice cooker into other electrical appliances to see if the voltage is normal or abnormal, so you can test it.

2. It is caused by the resistance or damage of electronic devices such as rectifier bridge and capacitor. If you have an instrument, you can take it apart to measure it. If not, you need to take it to the electrical maintenance station for maintenance.