1, the sheave is tired after long-term use, so the sheave should be replaced in time.
2. Dirty things get stuck in the wheel of the cable pulley. It may be that the conductor was brought in on the ground when he was late. Stop working, remove the cable pulley and check it carefully.
3. The cable pulley is exposed after long-term use. Because the air is wet and rusty, the wheels don't turn.