Howard Miller clock movements are replaceable. If the clock is under warranty, send it to a repair center after contacting Howard Miller customer service.
For clocks that are no longer under warranty, purchase a mechanical movement from Howard Miller or from a third-party distributor. Make sure the store is an authorized Howard Miller retailer. Howard Miller offers a list of authorized dealers on its website. Replace the clock movements as part of a DIY project by following the instructions that come with the replacement piece. For best results, opt for a professional clock repair service, especially if the clock is also in need of restoration.