I think I've isolated the problem, Opjose. I removed both aileron servos (glad I only used a small amount of glue - noob lesson #1), and plugged each directly into the aileron channel in the RX. With each I got the same result...buzzing noise, and no movement of the shaft. Although I had already determined that the aileron channel and TX controls were working properly in a previous test, I plugged each aileron servo into the elevator slot, and using elevator stick got the same results.

So, through the luck of the draw, it appears that both aileron servos are bad - unless you've got another suggestion I can try. Do I PM John for replacements?

Thanks.