I recently acquired a Data-2000. The person I bought it from said that he had replaced the batteries and it was working great. When the watch arrived at my place I found it to be not working, as in it looked like it was dead. We came to the conclusion that the battery he put in must of been mistakenly an older battery. So I took it to the shop and they replaced the battery and it came to life! Joy! fast forward a day and a half, I get up in the morning to find that it's dead again!! What is going on here? Now I'm thinking that the person I bought this from really did put new batteries in it and it died in the mail as it was coming to me. Anybody experience this before, or how I might be able to fix it?