Maybe I need another 'scope?
 

On Tue, 20 Nov 2018 08:08:50 -0500, Tim Schwartz
wrote:

Eric,

I'd suggest using a voltmeter (analog or digital, whatever you
prefer)for the DC voltage measurements. I like my old Heathkit VTVM for
troubleshooting, as you are unlikely to cause any serious damage to the
meter, as could happen with a digital.

The scope you have is all you need, as what you need it for is the AC
part of the waveform. Set the scope to AC coupling at the input and
you'll be looking at the ripple on the supply. If the ripple exceeds
400 volts (8 divisions at 5 volts each is 40Vp-p and with a 10x probe
that gets you to 400Vp-p) then something is seriously wrong with your
power supply or measurement technique, or you don't have a good ground
between the amp and the scope.

Regards,
Tim



SNIP
Thanks Tim. That was just the sort of advice I was looking for. I
don't have a lot of experience with oscilloscopes and every time I use
mine I need to make sure I'm very careful to get everything set
correctly.
Eric