Hi, I have a BeoCom 1500. Most number keys no longer respond to being pressed. Is this a terminal disease, or should I pursue some one to repair this?

I had the same problem with BeoCom 1600
Few buttons did stopped working. I was sure at the time that clean up would help. However I had to replace part (which was ordered from my dealer) Do not recall what was the name of the part but it's clear plastic with carbon coating in place of buttons.
Do not recall price but it was cheaper than $25 US.