An apparatus and method for stabilizing the frequency of a piezoelectric crystal resonator, especially useful in common emergency positioning radio beacons. A temperature compensated crystal oscillator circuit (TCXO) is mounted on one surface of a thin substrate. The TCXO includes a piezoelectric device such as a quartz resonator and a capacitor thermistor compensation network to reduce the frequency fluctuations of the crystal through variations in temperature. A heating circuit is mounted to the opposing surface of the substrate, thereby providing a thermal connection between the two circuits. The heating circuit includes a temperature sensor for sensing changes in ambient temperatures and a heater control amplifier for adjusting the power of a heating element. The substrate with the two circuits disposed thereon is suspended within a hermetically sealed enclosure by a plurality of support pins. The pins assist in supporting the substrate away from the interior walls of the enclosure thereby reducing heat loss. The crystal oscillator is therefore maintained within a certain temperature range while temperatures at which activity dips often occur are avoided. The invention is also a method for constructing an electronic component heater assembly, including the construction of conventional oven controlled crystal oscillators.