This compactor is the rectangular design made like the Whirlpool units. You can flip it over and remove the bottom cover plate to reveal the motor and chain drive for the ram. If you remove the top cover, you can check the ram power nuts
, which are the usual culprit. If this sounds Greek to you, it probably is. Use your model number to look at part diagrams to help give you an idea of these parts arrangements..I carry the Compactor manuals on my site if you are interested in repairs. It has all of the diagnostic procedures for checking things like the "reversing switch", plus the repair steps involved.