I have inherited a PACT precision chrono that I can't get to work. This thing has all the appearance of being from the 80s. My late grandfather in law passed it down to the one he knew would use it and my first attempts failed. I have it plugged in as instructions direct, overcast day, no shade or sun screen. I have cleaned the sensors. I have shot .22lr, 44mag, airsoft gun and even swung a baseball bat and can't get a single reading. I understand this is an old device and many would say just get a new one. This is not an option for me at this stage of life. It is this chrono or no chrono . I was just wondering if anyone out there had any experience with this unit and had any recommendations. Thanks in advance.