Need a cure for NS-9000

Hello everybody
I have a Northstar ns-9000, and the coarse clarifier has a detent in the middle of its range of movement. I am fighting trying to get someone on frequency, it seems it needs to be right on the edge of the detent and does not want to stay there.
Is there a way to cure this? The fine clarifier apparently is not unlocked for transmit, turning it does not help except for receive. Any help or info will be appreciated.

Thanks, Sammitch