[TinCanAlley]

Originally Posted by N2IXK

Where is your baseline set? Are you operating the scope AC or DC coupled?

Typically, for checking ripple on a power supply, you would operate AC coupled, so you only see the AC component of the signal, and ignore the DC. If you are running DC coupled, the baseline should rise a bit less than 5 divisions (250V) from zero, with ripple superimposed on it. You can do a quick sanity check with a DMM, by measuring the 240V supply twice, both in DCV range (should show ~240V), and in ACV (should show close to zero if no significant ripple is present).

From what you are telling us (5 V/div with a 10:1 probe and no auto priobe ranging), the scope is actually showing you 50V per division, or a waveform of ~75 Vpp. This is WAY too much noise on a supply rail, and would easily explain the jailbars.

You really need to learn how to use a scope effectively in order to get useful information from it. Take a couple hours and watch this GREAT YouTube training session:

http://www.youtube.com/watch?v=8ZKMrzTGxLQ

Gonna get some popcorn and watch that video.

Okay, just did a scope of the 240V line just after it comes off of the resistor into the main feed (where the capacitor is and the where the 240V gets distributed). I had the scope set to AC coupling, V/D set at .5, the T/D set to 20us and probe at 1x. The rippled waveform covered 1.75 divisions peak to peak. So that would make the AC less than a volt, correct?