What should I do if there is slack in the cables before resistance is felt?

Woven cable can stretch slightly when first used, so the cables will need to be tightened. For slack in the ab upright weight stack, tighten both the High Cable (85) and Low Cable (86); for the other weight stack, tighten the Rear Cable (87), Press Cable (88), and Butterfly Cable (89). Methods include tightening the 1/4" Nylon Locknut connecting the cable end to the bracket, or repositioning pulleys to a different hole in the U-Bracket. Do not overtighten, as this will lift the top weight off the stack. (Page 25)