I have used a Thsinde 18B+ Multimeter reliably for several years. However, it recently started to beep on any setting without giving a reading. I noticed that the display was showing a low battery even though I knew the battery was good. I thought the problem might be a high-resistance battery contact that had developed over the years, that was dropping most of the battery voltage, so sprayed all the battery contacts with contact cleaner. That fixed the problem.