Came across a switch-mode boost converter in a microwave HT supply today.~ normal magnetron. Output of the high frequency transformer looks to be a voltage doubler with 32x12mm film caps doing the job of the old 120Hz can.
Paderno Mwo021 seems to have had a pretty flakey reliability.
The controller in this one gives the magnetron supply three chances to produce a feedback amplitude, they quits.
The HT supply into the magnetron shows 'some' output during these attempts but is visibly falling before each cut-off.
I found a dry solder joint where the HT winding returns to the ref ground. I assumed this would have just arced over without much interference in basic function. Anyways behavior unchanged when restored.
Film caps and diodes next?
RL