I realize this a a basic question but I do not want to screw up the polarity or worse when I solder in my replacement electrolytic cap.
I am looking at part #54, a 16 mfd cap that is from what I read on the Ryder changes actually part #41. That’s no problem but I don’t know where connect my new 16 mfd cap.
I’m assuming the + connection for my new cap is to the three resistors currently connected, shown in the photo, but is the - connection made within the old cap. I would prefer to place the new cap under the chassis but don’t know about the - connection.
Any assistance would be appreciated.
Yes the one you have circled is the + terminal. - is connected to the chassis.
#56 the - doesn't connect to the chassis but to the center tap of the hv winding. That's why there's a cardboard sleeve around the bottom. It's to isolate the - side of the cap from the chassis.
It's not all that difficult the remove the old cap. Cut it open, drill two small holes for the leads of the new cap. And reassemble.
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
(This post was last modified: 08-25-2021, 10:15 AM by Radioroslyn.)
I am still confused. This #41 16 mfd cap only had the positive connection before. I don’t know where the negative to this cap was unless it was connected inside the cap because there was no second wire. Now you say to drill two holes, but where on the chassis is the negative supposed to be connected?
I’m used to seeing a solder point on the chassis but when I look I don’t see anything like that and I don’t want to attach the - to just anywhere.
Sorry but I am just learning this hobby and I do not want to mess the connections.
(This post was last modified: 08-25-2021, 05:03 PM by Phil27.)
Your original 16mfd cap has a positive post and the negative is internally physically connected to the can. When the can is mounted to the chassis then the negative side is grounded to the chassis. If the can is insulated from the chassis then the can must be wired into the circuit, usually not to chassis ground. When you replace it with a modern cap you must follow the schematic by connecting the negative lead to the appropriate point in the circuit. So, if the cap is stuffed inside the can you can drill two holes through the bottom of the can and make the appropriate connections. There are several descriptions here on stuffing electrolytic capacitors.
I see, so in this particular case, if I were to secure the negative connection inside the can, I have already cut the can open, I could just hook it up as it was originally with only the positive connection going to the three resistors.
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.
Thanks very much for all the help. Much appreciated! Due to Covid I’ve only had Youtube videos and this forum for help since I started this hobby and all the members are very willing to provide assistance, just what a newbie like myself needs.
