Hi, this is very basic. I just bought a couple of old Ampeg solid state amps from the late 70s which have been neglected. I've cleaned the pots and got them sounding good. They're pretty filthy outside and in. Is there any basic maintenance that should be carried out, like the replacing of filter caps on a tube amp? Would it be a good idea to try to clean the PCB, or should I just leave it alone? Finally, the power cords definitely need replacing. Any special issues about replacing power cords on these? 3-prong? Thanks for any guidance.