IR Thermometer LT300

[LT300 User]

I purchased a LT300 IR thermometer about three years ago and was happy with the performance for the first two years. After that, the measurements were no longer accurate. I mean they were off by more than 30 degrees Fahrenheit. I thought I just had to make sure the temperature of the unit had stabilized with the environment before taking measurements. However, no matter how many times I tried, the readings would fluctuate widely while holding the pointer in the same place at the same large object. More recently, I tried it again and it is completely defective and malfunctioning. I set the max and min to the widest range possible, but holding the trigger and pointing it at the floor or wall causes the reading to start off with fluctuations of around 50 degrees per second, then after a few seconds, the fluctuations are around 500 degrees per second, then finally it just beeps with a beeping sound and displays low at the top right and high at the bottom middle. It's now totally useless. I can't return it because it is out of warranty. I only was able to use it a few times over the 3 years I had it, so I am very disappointed. I tried resetting it several times and replacing the batteries but no luck. I tried varying all of the settings/modes, but nothing fixes it. It just keeps beeping when I click the trigger. Any other suggestions? Cheap Chinese quality!