I recently inherited a Hamilton Wheatland Mantel clock (circa 1985) and do no know how to get it started. All three windings are wound but it does nothing. I rotated it back and forth on both axis and nothing happens. On the bottom of the clock is a plastic tab that looks like it could hold a cord of some sort. Also on the bottom, beneath the chimes, are two slotted screws that look like they could accept wires. The clock came with a key and the instructions on the back plate mention nothing about electric power. What am I missing?