Yes, I had the same problem. There’s a kit available at home centers in the fan department. It has some weights with adhesive on the back and a clip on test weight. You put the clip on weight on the suspect “light” blade and try the fan. If better, you can stick a weight on the top of the blade out of sight. Keep going until it runs smooth. It works, but you have to be patient. If it’s on a vaulted ceiling or high place, it’s very tedious. It will work though, unless the fan is REALLY our of ballance, then you might try weighing and re-arranging the blades.

Have fun.