1, the mac cable is broken, that is, the cable connecting the screen and the motherboard is burnt or has poor contact. Just go to the after-sales store to change it.

2, the screen is broken, need to replace the screen, the price is higher.

3, the motherboard is broken, this probability is relatively small, but it does not rule out that the solution is to change the motherboard and get Apple's after-sales maintenance. It is mainly caused by the failure of the screen group, that is, the problem of the screen line IC.