[ms660]

Donald, regarding C3 and the tubular capacitor connected to the earth connection on the IEC socket, there's nothing too complicated about it, on your receiver there's an earth socket on the back of the chassis, in the schematic it shows that it's for a connection to "real earth" by real earth they mean a connection to an earth spike or rod banged into the ground, the function of that is to enhance the receivers reception but because the receiver is a live chassis design and the fact that it's earth connection socket is exposed to you or anyone else then a capacitor is fitted between the chassis and the receivers earth socket, that capacitor is C3.

Here's the reason, and it's a very important safety reason as to why a capacitor such as C3 is fitted to a live chassis design. As you should know by now the chassis of a receiver which is of the live chassis design can become live, that's to say if, for whatever reason, the mains live was connected to the chassis and power was applied and the receiver switched on then there will be full mains voltage between the chassis and earth, a potentially lethal voltage. The value of C3 is selected so that at mains frequency any current flowing via it will be low enough to be regarded as a safe level while at the same time providing an effective path for an earth connection for radio frequency currents.

A rake in the long grass waiting to be stepped on with your receiver is that even if the mains lead is wired up correctly the chassis can still become live if the receiver is still connected to the mains, that's because its on/off switch only switches the neutral and therefore with the receivers on/off switch switched to off the chassis will become live via the path provided by its mains transformer, you need to be aware of that.

The probable reason that the tubular capacitor (0.01uF) was fitted is as I explained in an earlier post, with a 3 core mains lead connected, the receiver would be earthed from a radio frequency point of view via the houses protective earth, which at some point will be connected to the "real earth" somewhere along your electricity supply line, the upshot of that is there would be no need to have a separate earth spike and its connecting wire which would normally be the case.

As said earlier I would remove that 0.01uF completely and if C3 is the original one then I would replace it with a Y class type of the same or almost the same value such as a 0.0047uF, or if you don't intend to use the earth socket you can omit C3 altogether.

Hope this helps.

This post might cross.

Lawrence.