Neil,

Scramble winding will reduce the coupling some but that's probably not
your problem.  I'm assuming the load on your "unregulated" secondary is
small relative to the load on your main secondary (do you have a
reasonable load on your main secondary?).  Odds are good that something
simple is wrong with your circuit.  Maybe you have the phase of your 12V
secondary backwards (try swapping the leads).  Maybe the diode for that
winding is inappropriate (high freq switchers don't work well with slow,
clunky 1N400Xs).  As Olin suggested, this would be simpler to
troubleshoot with a 'scope (even a cheap scope would let you check
phasing).  On the other hand, you can try checking some of these
issues.  Anything getting hot?

Best regards,

Dave

PicDude wrote:
>
> michael brown wrote:
> >
> > You are carefully winding the wire onto the form, correct.  You have to
> > wind the wire without cris-crossing it.  IOW, the turns should be side
> > by side and not crossing the previous turn, otherwise it's a choke and
> > not a coil.
>
> Yes, I wind very carefully making sure I don't overlap my previous
> windings.  I do however, "overlay" the secondary on the primary,
> except in one case where I let the primary take half the toroid and
> the secondary the other half.  There was absolutely no winding
> overlapping any other winding here.  But no dice still.
>
> Interestingly, I have a toroid from Coilcraft that surprised
> me -- there are windings overlapping other windings all over
> the place.
>
> Cheers,
> -Neil.
>
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