We have a GSD2500 purchased in 1990 for $500. It is in great condition inside and out. NO rust and very little signs of wear. But, lately during the wash cycle the PF error message shows on the display panel and the washer stops. First, is this easily a self-repair? If so, what parts do I need?? If not, is it worth paying to have it fixed even though it's a 1990 model. It looks like new so we'd hate to just dump it and buy a new one. Any help would be appreciated.