I turned on the Plus again today. When I flipped the power switch, there was the startup bong and, I'm happy to say, no loud fizzling!

However, when I put my ear close to the machine's top vent right above the analog board, I did hear a clicking sound, as if the fizzle were more "spread out" this time. At that point I turned on my small fan that I focus on the machine's exterior to keep it cool, and several minutes later when I turned the small fan off so that I could hear the Plus, the clicking had stopped.

So my guess is that temperature definitely is a factor here. I had plugged it in only the previous night when it fizzled that first time, whereas this second time it had been plugged in longer, with that trickle of power keeping it at least a tiny bit warmer.

Just theories anyway...if anyone has had a similar problem feel free to pitch in and share your situation, ideas, etc.

-Apostrophe