The Polaris clock is set to the minute hand.

The battery is down or the movement is broken.

Solution: 1 Take down the clock and look at the back. There is usually a battery box to see if the positive and negative poles of the battery are connected backwards.

2, or the battery is dead, see how many batteries are left, and go to the supermarket to buy a new battery to replace it.

3. If you don't leave, it may be that your exercise is broken and you can't bear to part with old things. Just buy a movement online (Polaris also available), and just change it. Generally, it will cost more than ten yuan. Now the movement is more advanced and accurate than before.