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Old 20th January 2013, 08:21 AM   #21
Elvee is offline Elvee  Belgium
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Quote:
Originally Posted by Fusion916 View Post

With just adding a load at the rectifier output to draw about 400mA I am getting the waveforms pictured at the OP.
Exactly that waveform? That is highly suspicious, you should see the regular 120Hz sawtooth, not this distorted 60Hz.
Can you post a pic of your set-up?
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Old 20th January 2013, 08:30 AM   #22
Mooly is offline Mooly  United Kingdom
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Did you try what I suggested in post #6 ?

Any result other than a perfect thin trace points to a wiring/test measurement artifact.
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Old 23rd January 2013, 05:35 AM   #23
gootee is offline gootee  United States
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I hope that more information is forthcoming, very soon.

A photo of the as-tested circuit is required.

I am wondering if the AC Mains input pair has any enclosed loop area, i.e. if it's not tightly twisted everywhere, or, if traces, if they are not extremely close together, everywhere. Same goes for secondary conductors going to rectifier bridge, and rectifier bridge to caps, and also for DC power/ground conductor pairs.

Leaving gaps between the conductors in any conductor pair that eventuially forms a loop makes what is called, in technical terms, an ANTENNA. And some seem to mostly transmit while others mostly receive. So minimize the geometric area enclosed by ALL (i.e. each) of them.
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Old 23rd January 2013, 06:05 AM   #24
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Sorry for the lack of update.

I have determined that it is partly a layout issue of the reference generator (TO92 bandgap reference), poor grounding, and where the scope ground was connected. I basically have to redo the layout grounding significantly.
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Old 24th January 2013, 02:24 AM   #25
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It would be nice if we could ALL learn from this.
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