To add to the discussion, I have some some cheap Korean / asian ???,
power supplies built for the Australian market here in my workshop
with failed flyback snubber protection for the main stiching
transistor / fet.

As an academic exercise i calculated the peak flyback curent for this
snubber design (app note design most likely) and discovered to my
horror that the units were designed to operate with a maximum of
120VAC input. What the supplier had done was to series wire the
input caps for 240VAC and not bother to check anything else.
Therefore the snubber network was under-rated. End result over a
period of time was stressed components and eventual failure.

Nino.
******************************************************
* Antonio (Nino) Benci                               *
* Chief Technical Officer                            *
* Monash University - Dept of Physics                *
* Wellington Rd, Clayton. 3168                       *
* Victoria, Australia.                               *
* TEL - 61 3 9905 3649, FAX - 61 3 9905 3637         *
* EMAIL - nino.benci@sci.monash.edu.au               *
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