Terry is right on. I use a old TEK 2221 Digital Storage and this way you can take a snap shot(very useful for unstable signals)Trigger on some point plus delay, then scroll through the captured data on the second channel. As Steve said in the previous post Osc Scopes with a little ingenuity can get to the problem. As for me, Logic Analyzers took me longer to figure out than the problem.

If you ever want to get fullest advantage out of your scope you need to take a training class from the vendor.

Joe