13 Jul
2011
13 Jul
'11
11:27 a.m.
On 09/07/2011 21:13, Tony Duell wrote:
Thanks Tony, you caused me to double check things...and it looks like
there's a couple of spikes on the ground of about 4Vp-p and 3Vp-p @
Hang on a second. What is the 'scope probe ground lead connected to, and
what is the 'scope probe tip connected to?
If the 'scope ground lead is connected to the 0V rail and you are seeing
4V spikes on something else that's supposed to 'ground' (i.e. also
connected to the 0V rail) then either you have a very serious ground
bounce problem or there's an open-circuit somewhere.
Looks
like the +12V startup and -12V (actually -15) are fine. I'm
Have you checked
these with a 'scope? Excessive ripple on a supply line
could cause exactly the fault you are seeing.
Ho 32Khz which was throwing all my measurements out.
I'm guessing a cap,
does that sound about right?
32kHz sounds to me like the switching frequency. If you're getting ripple
at that freqeucny, I would suspect the capactiros on the DC output side
of hte rectifiers.
-tony