Juno-106 Slider Issue

Hi I have a Juno 106 and the decay slider is buggy.
It registers maximum and minimum but the values in between just souns as max or min as well. Theres no in bewteen. I know one of the voice chips in mine needs replaceing so i use it in poly 2 mode which avoids the issue.
If I replace the slider with a new one will that fix it? or is the issue somewhere else?