08-26-2021, 08:38 AM
Phil, if you opt to rebuild the can, the negative lead of the new condenser will go to the can, and the positive to the post of the center terminal. If you have taken one of these condensers apart you will have noticed that the center post goes to a wavy aluminum plate, which is surrounded by a mesh made of an insulating fiber which lets the electrolyte fluid flow through it. The can itself forms the other plate of the condenser. On most of these old Philco receivers one of the cans will have a cardboard insulating sleeve around its base. It will also have a second contact strip slipped inside the cardboard sleeve, which is used as the negative terminal. This condenser is used to smooth out the negative bias voltages, and must be wired in according to the schematic, and NOT case to ground like the other electrolytics which smooth out the B+ voltages. Be careful that your solder joints are good when soldering to the inside of the can. You will be soldering to aluminum, which can be very difficult. Many of us opt to just drill through the can base, and use two wires, one black for negative, one red for positive. If you opt to solder to the aluminum, lightly sand the area to which you will be soldering immediately before you solder to it and paint it with some rosin flux. this will remove the coating of aluminum oxide, and allow the solder to bond more easily. You can make the rosin flux by dissolving powdered violin rosin in isopropyl alcohol. You can get cheap violin rosin online from eBay, or at any musical instrument store.