I just use my cantina (cold cellar) in the basement during the winter to make salami. As long as you can control both the temperature and the humidity you should be fine.
When you say doesn't seem to be working, are you getting proper desired temp and humidity and then meat is just not coming out right?
I am asking whether you feel it is the chamber itself or possibly your curing process/ingredients/techniques.
We dont have a stand alone hygrometer because its built into the humidifier.
Hydrometers are inexpensive so that would be my first stop... Have you looked at any of Marianski books? Great info