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From: legg <legg@nospam.magma.ca>
Newsgroups: sci.electronics.repair
Subject: Switch-mode microwave HT boost in Paderno MW
Date: Sun, 05 May 2024 12:32:50 -0400
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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