Spouse has a 1980s vintage hybrid with twist shifters. For some time now the front derailleur will not shift it to the big ring and the twist shifter will not make the click. If I tug the cable by hand it will not shift either. I messed with the limit screws (which I am an amateur at and I am easily confused about which screw does what) but it does not help.

If this is relevant, I do think that I may need to put a new cable in anyway because the cable is broken off at the anchor point so there is no ability to adjust cable length.