My SD,with all paper work when new,had 3 amps. installed.I guess the owners gave up.My solution was to unscrew the amp.,take small screwdriver and slide the cover off amp.Then insert 2 water hose washers in cap,reassemble and screw back on.It like helps pins go deeper in socket.No problems 2 years.
I've heard some take a metallic paint and paints the contacts,or drive up socket pins.