I have an 8566B, when you perform shift 8 to begin the adjustment routine the wave is fluctuating. the peak is within tolerance of .2dbm but the rest of the wave is choppy. Also when you put the unit in 0-2.5 Low band the noise floor and the harmonics are jumping left to right at approx. 200 MHz Range. I have isolated the problem to the RF section and determined that that electrolytic's in the power supply are operating properly. My next course of trouble shooting is the YTO but I was hoping someone would have an idea of anything else I could look into.