Sorry to bring up an old post, but has anyone found a cause/solution for this? I have a V570 in the field that's several years old that's just started doing it. The software/firmware has not been touched since it shipped, and has run trouble free for thousands of hours. We don't have easy access to the controller for testing, so before I ask him to ship it in/replace it, I wanted to see if there was something else to check.