I'm thinking it might be time for some photos.
Can you take a photo of your setup? It should be close-up, well lit and in sharp focus for us to see exactly what's where. Show it with the scope probe attached, so we know where everything is.
Also, images of what is on the scope's screen - one for the pot at minimum, middle and maximum positions, if possible.
Two other questions -
- What are you using for a power source?
and
- Where is the scope's ground clip placed?