Phillips REMstar Auto A-Flex control switch problem

The control switch on this unit has become erratic and I'm wondering if it can be replaced. Here's a brief description of what's happening. When you press the knob downwards it's likely to change between the different options on the initiation screen. When I finally get it to the correct one to start delivering air and begin to turn to the setting number, the numbers light up all around the dial as if I'm turning the knob between the different numbers, but it's usually not sequential. This is my second machine and I've had it for several years. The first was a similar model by the same manufacturer and ultimately was replaced for the same reason. Other than the control switch issue, the unit works fine and I'd like to fix it while I wait for the replacement from the Phillips recall. Any advice will be appreciated.

Is this machine a System One model? Is it a 50 or 60 series?

If so there are replacement knobs.

https://www.directhomemedical.com/contr ... -cpap.html

If not a System One model...need more information or a picture.