Why didn't the one-plus prompt sound stop after the screen was lit?

The common reasons why the phone can hear the sound when the boot screen is not bright are: First, the memory is loose or there is something wrong with the memory itself. Try inserting the memory again or replacing the root memory; Second, the motherboard power chip is welded or aged, the shielded wire is loose or the motherboard power circuit is short-circuited; Third, the graphics card, South Bridge and North Bridge BGA packaging chips are welded or damaged. Generally, there are many cases of virtual welding, so it is good to add welding.