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sci / sci.electronics.repair / Switch-mode microwave HT boost in Paderno MW

Subject: Switch-mode microwave HT boost in Paderno MW
From: legg
Newsgroups: sci.electronics.repair
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Date: Sun, 5 May 2024 16:32 UTC

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From: legg@nospam.magma.ca (legg)
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?

Subject	Author
Switch-mode microwave HT boost in Paderno MW	legg