Had an interesting experience with my laser last week. I have aa Epilog EX75 Watt Laser purchased in 2004.
It went crazy. the carriage would slam all the way to the front then to the back. With a lot of help from Epilog tech support we decided it was the Y encoder strip. They sent me a new one and charged me about $80 and now it works great.
Here is the interesting part. For the last couple of years when I start the laser it has been taking longer and longer to fire. I have been dreading replacing my laser tube since I was sure that was the problem. Replacing the Y encoder strip seems to have fixed the slow firing problem. We also cleaned the X encoder strip so that may have helped also.
Lesson learned. I will clean the encoder strips more often.