[Cape Codder]

Those old clocks are actually mechanical with an electric winder. Inside is a set of contact points that get dirty or corrode and may need a little filing . When the points close it creates a electromagnet that pulls the winder and opens the points the clack runs mechanically till the points touch and rewind again. Pretty basic ,I am no clock repair man but have fixed a few of those over the years. They usually have an adjuster to speed up or slow down as needed.