Braccio Tinkerbot Gripper Issue

I am using a Braccio Tinkerbot and I am having trouble getting the gripper to work. The servo doesn't seem to be strong enough. I plugged an alternative servo into the board and I am receiving accurate results for what it is to do. I am curious on what to do or if anyone has had a similar issue, how did you fixed it?

I have no special idea nor experience with that bot.

Two servo types are listed, with 12kg*cm and 3 kg*cm. If an alternative servo of the same type (torque) works, the servo is defective. If a stronger servo works, check the assembly of the gripper.

Can you plug the gripper servo cable into a different connector and test again?