[sdiy] Weird Ripple Voltage

[mike ruberto]

I'm thinking I have a bad snubber cap. However, before I take any
drastic action I am trying to educate myself in the topics of ringing
and snubber design. So far this has been most helpful...
http://peufeu.free.fr/audio/articles/Snubber%20Networks%20in%20Power%20Supplies.pdf

The math is quite above me though for the most part. Still at least I
have a better idea of what's going on.

Considering the negative rail is not having this fault at all I will
assume the proper values are being used for this supply and start
replacing the snubber caps one by one in the positive rail rectifier.

This whole experience makes me wish I had better test equipment ;-)

Mike

On Sat, Apr 5, 2008 at 3:40 PM,  <KHeck73 at aol.com> wrote:
>
>
>
> I've had some weird experiences using the same AC power circuit that powers
> dimmer controls for lighting. If your lighting is usually on, try switching
> it off and see what happens. For my circumstance, I think it was the square
> wave off the triac making harmonics...  -Karl.
>
>
> In a message dated 4/4/2008 9:41:25 P.M. Eastern Daylight Time,
> somnium7 at gmail.com writes:
> More strange power supply problems. This time I have a high pitched
> whining in the audio. I traced it back to the devices power supply
> where it seems to be originating before the regulator. On the scope I
> see a ripple voltage with the usual saw shape but it is shot through
> with  lines. Increasing the volts division I can make out a tiny
> sawtooth wave riding on the ripple at several times the ripple
> frequency.
>
> I disconnected the regulator to verify the origin and sure enough it
> coming form the rectifier/filter stage. That stage is a bridge
> rectifier with a ring of snubber caps and then the main filter cap and
> another 0.1uF cap. Am I looking at a problem with the bridge rectifier
> or is one of the snubbers bad?
>
> Mike
>
>
>
>
>
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