Figuring out the hum in my vintage AM radio

The constant buzz was driving me nuts. I traced it to a bad ground wire after testing each component. A simple solder fix and it's silent now.

4 comments

4 Comments

saraht153mo ago

Remember that hum in old AM radios usually comes from dried-out filter caps. A bad ground can do it too, but caps are the first thing to check.

victorw433mo ago

Like when I replaced every cap EXCEPT the bad one, right @saraht15?

grace8926d ago

The 60Hz hum I ran into last month on a 1950s Hallicrafters S-38D turned out to be a bad solder joint on the tube socket pin, not caps or ground at all. Caps are the easy lazy guess everyone jumps to first, but I swear half the time it's a corroded ground wire or a cracked trace on the chassis. Dried out caps are common sure, but let's be real, if you're chasing a hum you should start with the power cord and work backwards, not just shotgun replace caps. Sometimes the simplest fix is to reflow the ground connections on the filter cap can itself if it hasn't been changed in decades.

drewgonzalez3mo ago

Actually I fix more bad grounds than caps.