[BrendaAnnD]

The yellow wire is the antenna. Black is ground. Your four wire group is your battery, which has connections for B+ and filament. This set is what is called a 'farm radio', and only runs from battery. It was not designed to run from household AC, it was made for rural areas where there was no electricity available. The colors on your battery plug don't match the ones on the schematic that I have. Perhaps someone else here can shed some light on that. Please note that applying power (any power) to the wrong leads can damage your radio if it is not connected correctly.