The unit runs but no water accumulates in the bucket and the basement is clearly damp

There are 5 basic, yet solvable reason for what you described. Please pay particular attention to numbers 1 & 2..

1. The humidity extraction level is set to HIGH. Lower it to 32-35%. If you have a manually
Controlled model, set the knob on Maximum.

2. Air intake filter is dirty or clogged. Turn unit OFF, & Unplug the
Unit, before removing to inspect & clean it, if necessary. If washed,
allow filter to completely dry before reinstalling. DO NOT operate
the unit without the filter.

3. Obstructed air flow. Maintain a minimum of 12 to 18" of clear air
space around the entire unit.

4. Cooling coils are dirty and need to be cleaned. Use warm water & dish washing liquid to
clean the coils. Rinse and wipe dry. Apply a light coating of WD40 to the coils.

5. Ambient air temperature at floor level is between 40 - 60 degrees.
dehumidifiers do not work well between those temperatures
(Unless, you have a Low Temp model). This applies mainly to
where the air temperature at floor level is colder than at shoulder level
in basement applications. Raising the unit up off the floor,
onto a sturdy table, counter top, etc, that can handle the weight
of the unit, plus a full tank of water, will usually resolve this
problem.

If none of the above solves the problem, it may be a case of the compressor needs to be recharged with refrigerant gas or that the humidity condenser sensor has failed. These things usually occur in units that are 5 years old or older. It's rare in a unit younger than that. But, it can happen.

Hope this has helped you to troubleshoot and solve the problem. Please let me know. Thanks