Yup they are pots. We used WD40 but it was rare one
got so noisy. That assy was a bear to work with so
dont tear it down unless a last resort. In the olden
days you could buy it exchange. Since they always had
a new triac & isolator that was half the cost plus the
labor saved dealing with it. The cover is just a cover....
73 Zeno
LFOD !