Help, Strange Static Sound Recurring

You guys are the best! I'm tied up tonight, but tomorrow will begin with the systematic experimentation.

I have never seen a group with such thoughtful advice on any subject. Again, I thank you for the technical and spousal advice.

Hy there's one other very basic issue that I forgot to mention, which could be the cause of this intermittent noise. We sometimes "look too deeply" into a technical problem, neglecting the basics which those of us that are more-experienced tend to take for granted.
This very basic issue is cable contact cleaning. As you are new to this, I'll explain again briefly here & then drop in the link to Galen Carol Audio's excellent website; under the "archives" section are many tech. tips that you should become more familiar with. Look over his whole website, read & learn a lot!
What happens over time is that your interconnect cable ends, panel-mounted equipment jacks, speaker cable connectors & ends attract dust, dirt, oils from skin contact, metallic oxidation occurs. This contamination causes (1) sonic degradation (2) possibly noisy connections esp. at the signal-interconnect level. One of the best & most popular contact cleaners is a product called Kontact, widely available, & one of Galen's favorites as well. If you're hesitant to spring for a $40 bottle of this "magic sauce" then at least get a small container of pure denatured alcohol from the drugstore; do not use isopropyl alcohol etc. as it contains lanolin, an oil which attracts dust right back into the connections, and water among other contaminants.
Cut some pipe cleaners into 1/3 sections & use those as your mildly abrasive applicators. Dip into the solvent & then scrub the cable connectors clean, both inside the contact point tips & around the shields. Also go around the outers & inners of your components' jacks, first ensuring that power is turned off. Also clean your AC cords, the mating female IEC's, speaker output posts, posts on the speakers themselves, & speaker cable ends. Change applicators when they become dirty looking & be sure to do that critical "second cleaning" as Galen explains all in great detail. If your intermittent noise is related to dirty contacts then this should fix that, & even if not then you'll still benefit from sonic improvements that can sometimes be dramatic in cases of gross neglect.
Here's that link:
http://www.gcaudio.com/Archives/howto.html

I took Bob's advise and cleaned all contacts with denatured alcohol. I plugged the amp back in and ... no power!

After checking around, I found a blue wire from the PC board on the side to one of the connectors on the back had become threaded between two speaker wire contacts. When I moved it, the amp powered up fine.

Then I hooked up everything else, and at least for now, the stereo sounds GREAT!!

Well that success was short lived. We enjoyed music all Saturday, then went out for dinner. When we returned the sound was back. I haven't done anything with it.

Bob, who do you know in Minneapolis?

Hyoster, I have a same problem withn my low-fi Yamaha based surround system. The Amp/pre amp is now 11 years old and white noise problem started 2 years ago with my front surrounds ( this is 7.1 channel system. I did not need those so I used only 5.1. Now the rear right channel has started same problem, intermittently, and I can't find a problem. I assumed 2 years ago that thoes two channel was 'shot'. May be it is as simple as speaker cables or interconnect having a short.(like a post above suggested) Try using diffrent cables (new from radio shack or equal)and see if still comes back. I will try the same.