I woke up one night to that horrible burning motherboard smell. Ran into the office and noticed it was the UPS. Somewhat freaked out (would have never expected that to go on me in this manner). I unplugged it ran downstairs and put it in the middle of the driveway. After watching it for about 10 minutes I went back to bed. Disposed of it two days later (after taking the battery out to eliminate a runaway effect.