On 28.02.2016 19:06, Dimitrij Klingbeil wrote:
On 28.02.2016 16:18, Cursitor Doom wrote:

[live power resistor procedure testing snipped]

Actually I did do this a while back without knowing the risks! As
you can see, I survived to tell the tale. All I was seeing was
about 30V of noise across that resistor but that was before I was
informed of the importance of hooking the supply up to a load, so
the test was probably invalid.

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.

P.S. That voltage estimate has probably surprised you. Unless one looks
at the circuit schematic and adds all the voltages from all the storage
elements (inductors / capacitors), considering timing and phase, it may
not be obvious that the thing was intended to run at such high voltage
levels. But there's a reason why they used a 1500 V transistor in it.