I had a strange noise in my rumpus room yesterday and I was afraid that my computer's power supply was about to fail. It was a high pitched monotonous beep that was faint but loud enough to be heard. I shut the computer off and the sound persisted. After searching all over, and not being able to get an aural fix on it, I opened the case of my Pact chronograph. I had left it switched on, and the battery drained. I guess that's the sound the unit makes when it's complaining about it's battery going dead. Drove me nuts for about ten minutes.