Switch-mode microwave HT boost in Paderno MW

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