I have 2 Mitutoyo digimatic calipers that I have had since the early 2000's. Purchased at the same time, the serial numbers are are only 3 numbers apart. I use both constantly and they have been good. Lately, I have found myself resetting zero more than I thought I should on one of them. I finally decided to send the questionable one back to Mitutoyo for calibration. While surfing the net looking for what it would cost, I found a video showing how to replace the display. Ive always wondered if they were getting dirty inside so I thought I would take the flaky one apart and clean it. Upon disassembly, I did not notice any dirt to speak of, but did see traces of oil or cutting fluid, not much and on the stainless only, not the electronics. I went ahead and wiped down the circuit board and bar with some rubbing alcohol. After reassembling, the unit worked perfectly, and was displayed within a half thou of the other ( I know they really cant resolve a half thou). After cleaning the other unit, both work and give the exact same readings, and both correlate to pin gages and my Mitutoyo digital micrometer. Good enough for me and certainly more consistent than they were.