I have pioneer sx 1980 stereo receiver. Manufactured 1978-82. I have re capped all of the electrolytic capacitors except the 4 large filter caps. The old caps are marked BLACK-NEG on the side. There are no markings at the screw terminals. The new caps are marked POSITVE on the side. There is a plus mark on one screw terminal. Im not sure how to connect wiring to new caps. Help needed please.