Cam follower preload is the amount of spring force that is applied against the cam follower.
Use a pull force gauge and measure the amount of force necessary to move the cam follower from the take-up lever cam.
Current procedures require the use of a fixture to adjust the cam follower preload. This requires that the color change housing assembly be removed and shipped to the factory for repair.
If the cam follower preload is out of specification, contact Melco Technical Support for instructions.