20 Jul
2006
20 Jul
'06
4:33 p.m.
I wonder what those are? they don't sound
rignt to me, I would have
expected a 2-level singal only. I asusme all the power rails are nice and
stable (sorry, I've had that one all too often...)
Threw the scope on them, 5v looks O.K. (about 2.5x background noise (I'm using
unshielded alligator clip leads, no probes yet). -5v +12v and -12v are all quite noisy.
I don't know if this is a recent development (I checked it out
after replacing some caps in the 5v section), or if the trick of using a DMM in AC mode
to check for noise doesn't
That depends on the DMM. Try measuring a battery on the AC range. If you
get a voltage reading, then you DMM responds to DC voltages even on the
AC ranges, at which point it won't indicate ripple correctly.
-tony