The weight system cables too short.
In many cases, cables appear to be short when they have not been routed correctly. The user’s manual should display the correct length of the cable. Measure the cable to be sure that it is the correct one for your machine. Check the assembly of the weight machine, and re-route the cables. If the cable is less than ½” too short, the cable can be stretched by pushing the cable down and inserting the weight pin in the bottom weight stack. Let the cable stay this way overnight.
2. The weight system cables are twisted.
Cables can become twisted when the pulleys they run on begin to wear down or do not spin freely. Every month, check that each pulley is spinning freely. Pulleys can be lubricated with a light multi-purpose oil. Cables that are twisted need to be completely removed from the machine, and laid out on the floor overnight, allowing them to untwist.