A plotter I worked on last week was giving 79:04 error codes and 86:01 and yet the plotter just needed to have the covers removed and all the collected years of dust removed...a spray can of compressed air and a big fluffy paint brush and we were back in business. No more error messages.
If you have your plotter in an environment that is going to be dusty, make sure to cover it. I use big flannel backed tablecloths from the dollar store and a friend uses a big outdoor grill cover. You could even make it out of clear vinyl.
If you are using it so much that you don't want to cover it, at least use the compressed air can and blow it all out every month. And when you are done with the blow out wipe down the rail and put 3-4 fresh drops of mineral oil, baby oil or 3in1 oil on the rail...be careful not to get the oil on the silver encoder strip...if you do wipe it off with a soft piece of cloth. Do not scrub the encoder strip!
With just a little love and attention your plotter will continue to produce for many years!