I am replacing the capacitors in my RCA radio, this is my first attempt. I noticed on the schematic that the electolytic capacitors are shown connected to ground, on the radio they are connected to the chassis. How can they be connected to ground if the power cord only has two prongs?

:I am replacing the capacitors in my RCA radio, this is my first attempt. I noticed on the schematic that the electolytic capacitors are shown connected to ground, on the radio they are connected to the chassis. How can they be connected to ground if the power cord only has two prongs?

Hoo,boy Petee, this is something that has to be explaned every so often, so let's have a course on ground 101. In radio, and other things, ground means a common point. There is Earth ground, that thing that is the third prong in your AC plug,and that is where lightning likes to go. There is chassis ground, and there is common ground. If you were to work on airliners, you would have AC grounds and DC grounds, and signal grounds and several other grounds, which connect to the airframe. Your capacitors are connected to chassis ground. It is a bad choice of words, but somebody named it that way, and we are stuck with it. If your RCA has a power transformer, then chassis ground is seperate from earth ground. If it has series tube filaments, it is what is commonly called an AC/DC radio, and the chassis may be connected to earth ground, or the 120 Volts, depending on exactly how the radio is wired and how the line plug is in the wall socket. You would, in my opinion, be better off if you thought of these common connection points as "Earth", "Chassis", or "Common" and except in the case of the first one, forget all about the ground part. In the case of a AC/DC set, some people solder a piece of copper wire to the plug, so it will only plug into the wide prong of the wall plug, and modify the wiring so that the wide prong (which connects to Earth eventually, even if it is called the Neutral). The hot prong is connected to the ON-OFF switch, so that when the radio is switched off, the chassis is connected to earth, and there is a minimum of 120 Volts running around inside, making for a very much safer radio. But once again, the capacitors are connecting to chassis ground, which I prefer to hear called "the chassis". I would suggest you study up on those AC/DC radios, for despite the fact they were at one time the most popular piece of electronic equipment built, they can be as dangerous as a rattlesnake. Give us the model number, and I will know a little bit more about what I am talking about. Look up a site called "Fun With Tubes", this guy knows his radios.

Lewis L.

The main thing is to check if the old cans are actually going to chassis ground, as there are situations where these can be isolated as well.
I've also seen where the tuning condensors are not grounded.
Basically, just make sure the plus side of the new capacitors are wired to the non-ground-side end, and wire the "can side" or "minus" to exactly the same place the old ones were wired to.