The reasons why the main control board of Bear Health Pot is not lit are: power supply problem and main control board failure.

1. power problem: check whether the power supply is plugged in and powered on. If the power supply is plugged in, but it still doesn't work, you can replace the power cord or try to connect to another power outlet.

2. Main control board failure: The main control board itself fails and needs to be replaced. It's a product quality problem, you can contact after-sales service.