That's why I checked very carefully, including checking for connectivity. There's only 6 wires! VCC,GND, SDA,SCL and 5V + and - for the servo array. And the wall wart for the Nano/Uno. I hooked up one servo only for the test. Not a lot of room for error there. And I'm using the Adafruit software to test with. I've gotten the same results with two different Nanos and an Uno, and two different servo controllers. Today I got really paranoid and switched to a different powerstrip and wall circuit. I've got the Adafruit source and my next step is to reactivate the debug print statements in it. But I think I'll do something else for a few days and come back to the wiring after a rest. Thanks for the suggestions.