[sdiy] Noisy Power Supply

[Scott]

I did a little more testing on my power supply.  I hooked my scope up,
and I can see an inverted saw wave on the negative side.
----|/----|/----   Sort of like that.  The positive side was flat.  I've
learned a lot about how to troubleshoot a synth module, but don't know
where to begin on a power supply.  Is there a common component that
could possibly cause this problem, or is it not worth trying to figure
out?  It was a fairly inexpensive ebay purchase.  
I'll just hate to have to wait to find another power supply.  Once I've
got it, I can plug in all of my modules   and call 3 years worth of work
done.  (although I have more modules 1/2 completed, and not enough room
in this cabinet I just made for it.. work will never be done)

Thanks