i went through all the recommended tricks and twists and nothing worked. fortunately, i had a second working device and so made some comparisons. I noted that the on/off button on the "dead" machine did not seem to have the same level of minuscule motion when pressed that the working device's button had. So, i took some tweezers and basically pulled up on the on/off button of the dead device and voila! fully functioning.
Seems like the on/off button can get pushed down and, thus, stuck in a down position. That seems to prevent the device from showing any signs of life. Unstuck it (if its stuck) and see what happens. good luck.