Apparatus and methods are disclosed for evaluating degradation of a transistor in a cross coupled pair of an RF oscillator independently. A MOS device can be coupled between a separated center-tap inductor. By appropriately sizing the MOS device and turning the MOS device on during operation of RF oscillator, a good contact can again be made that allows the oscillator to operate at design performance. By turning the MOS device off, the supplies can be separates such that I-V characteristics of both transistors of the cross-coupled pair may be obtained.