bill, just hick talk for getting shocked when touching the cover screws. i did find the problem. a poor wiring job to begin with because the equip gnd was snipped off the supply cable. the gnd wire in the 14/3 feeding the light/fan combo from the switch was terminated on the switch gnd screw and and the fan housing with a potential of 120v. found that the nm cable clamp had been overtightned to a point of mashing not only the nm sheath but the wire insulation of the ungrounded wire as well to a point of contact between the hot wire and the clamp.
not sure why they went to the trouble of grounding the fan and switch and omitting the main equipt gnd cond from the source.
