Jon:
Thanks for the reply. I followed your suggestions by going to the Apple help page (not the open forum). The more I thought about it, the more I think something will have to be replaced--either a battery or a switch or both. I'm scheduling an appointment at the Genius Bar ASAP. Your suggestions were very helpful. Thanks.


Mac Pro dual Quad-Core Intel Xeons Early 2008; 16GB RAM; MacOS X 10.11.6, iOS 9.3.5