Are there any signs the rubber buttons are decaying, or is it just dirt, grime, etc. that appears to be making them stick? I'd check with Digitrax customer service for advice on what to clean them with.
I *think* you have to slide the back cover slightly up and then it comes over easily. Think how the battery cover slides off and the back cover slides off similarly but in the opposite direction. It's been awhile since I had mine apart to install an on/off switch so I can leave the 9V battery in when not in use. When you say the buttons stick a little are you referring to the rubber nodules or the actual switches? The switches are sealed membranes (in one complete panel) so they shouldn't switch unless they are defective. If rubber nodules, look for burrs on the hole openings and deburr as needed.
I checked it under my new new magnifying head gear. It is mostly the buttons on the left side. Looking at them they 'tilt' to the left as opposed to sticking straight down if that makes sense. I brushed around the buttons with a toothbrush dipped in 91% IPA. It seems to have helped a little. I think I will brush them again tomorrow.
