I have several Oregon Thermometer devices here which have failed. Most of them are TH138's (long since obsolete), with remote sensors, and had been installed in damp or wet locations. More than likely the sensor element is a simple thermistor. Wondering if anyone has an idea of the value of the thermistor in question. It's easier to ask than to disassemble a good unit, or to waste money on ordering a selection of thermistors to try.