Focus demand tension adjustment

I have been installing 4 studio cameras in college media studio and have attached zoom and focus demands. 3 of the 4 focus demands are extreme loose and almost ‘free wheel’ and the slightest touch moves them out of focus. The 4th focus demand has a nice level of resistance and feels like it working correctly. Is there a way to adjust the tension of the focus wheel. I can’t seem to see any sort of adjustment or mechanism.

Seems like nobody else is having similar problems. I did open up the device to take a peak inside, there are 3 tiny screws around diameter face of the face which the branding is on, this got me inside where I found a few more screws that I removed. But then didn’t see anyway I’d dismantling further without possibly breaking. I was hoping for some sort of screw/tightening part that would increase the friction on the focus wheel but nothing was visible.
Has nobody else has a loose/low friction wheel? Maybe I have just got a couple of bad ones that I might have to RMA.