When your antique radio hums, it’s never a happy tune. Speaker hum is almost always the result of electrolytic capacitors gone bad—one of the most common problems in old tube radios. Because capacitors (also called condensers) are inexpensive and have a short shelf life, it’s simpler to replace them all—a process old-time repairmen call “recapping” a radio—than to test and replace individual capacitors. The most practical way to do this is to mount replacements under the chassis. In no time, you’ll enjoy the rich bass tones of your old radio without the monotonous 120-hertz hum. Writer Bio
