On Sun, 28 Feb 2016 19:06:38 +0100, Dimitrij Klingbeil wrote:

Also, even with a dummy load connected, the stray capacitance of an
oscilloscope, when hanging off the loose end of a power circuit with
some 800 to 900 V worth of HF on it, would probably cause so much undue
capacitive loading that the power supply circuitry would hardly handle
it.

Isn't this just another example of the unsatisfactory nature of this
resonant converter design? If the thing is *that* fussy that a little bit
of stray capacitance can catastrophically destabilise it, then AFAICS
it's a fundamentally unreliable topology and it would be better to have
used one of the non-resonant forms of converter. Unless there's some
compelling reason I may be unaware of not to for oscilloscope power
supplies, of course.