I learn things every day. Today it was that not all power adapters are created equal... and I always knew this, but what I did not know is just how the OUTPUT of a Switching DC Power Supply is NOT like that of a (traditional) Linear Power Supply. Simply put, a Switching Power Supply does not provide standard DC output, without the cicruit be completed (pos to negative closed circuit). Without the reference "0v" connected, the waveform delivered is as shown in thumbnail.
To make Stan's circuit work correctly, you can NOT use a Switching power supply.