Another thing: since che 475 and 465 circuits are very very similar (I own a 465), the waveform on CR566 in effect is more dirty than CR556. It should rensemble the waveform of CR556 with superimposed a train of spikes a few mV high on the upper portion of the waveform.
In any case, during the commutation, the voltage swing on anode of CR566 MUST be around 500mV. No less, no more.
Both 465 and 475 Tek manuals stated that.
Max
