oh man, that was easy! you'll have to excuse my low level of technical competence, i'm learning each bit as i have to deal with it, but there was plenty of adjustment available at the barrel on the cable end at the derailleur. a bit of wind on that, and slight tweak of the stops and its back to the slickness. too easy! getting down on my hands and knees i could see the alignment issue at the cassette that was pulling the chain off the gears and causing the irritating squeak. problem solved. thanks all.