On 28.02.2016 22:33, Cursitor Doom wrote:
On Sun, 28 Feb 2016 19:23:20 +0100, Dimitrij Klingbeil wrote:

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.

And yet C1804 is rated at 'only' 630V. Weird!

That's not a problem. It only ever sees 320 V from the mains, plus any
little remains of the mains surges that may come its way past C1802+3.

Even with surges and such, 450 V is likely the highest thing it will
ever see, so a 630 V rating is a good and conservative one.

It won't ever see the 800 V. But the transistor V1806 (collector) will.

Basically, the input caps will "see" only normal rectified mains (320
V). The resonant caps will also see some 300 to 320 V, but because the
sinewave resonance signal is bipolar, and one end is tied to the
positive end of the input caps, there will be times (each half cycle)
where the voltages will add and the result (referenced to the emitter)
will reach some 600 - 620 V. At these same times during the cycle, L1806
will also be reset via V1811, and the reset voltage (some 200 V, also
being in series) will also add to this, plus any little remains (50 V or
less) from the L1804 circuit. So the collector of V1806 will "see" quite
a lot of voltage when V1806 is in the "off" phase. But this high voltage
only applies to the V1806 collector, not to the other parts / signals.

Dimitrij