[Jamie]

Update - I tried tapping on everything with a wooden stick. No problems. So, using Brenda's milk crate idea, I put a cardboard box over the chassis (I know, I know, it's flammable) and let it play all morning. Once more, no problems. It is 12:52pm here now and the chassis and speaker are back in the cabinet.

I am sure it will quit playing now, so I can start all over. The only clue I got was, twice, the bulb for the shadow meter got a little dimmer. It only happened for an instant, and I could detect no shorts, nor could I recreate the condition. It never went out, nor would I even say it got dim. It just lost some brightness for a split second, twice. It is very hard to describe, and now I am even wondering if I imagined it. It is a brand new bulb. Perhaps this clue will give someone an idea? Thanks to everyone who has responded. You guys and gals are the best.