Radio makes strange noise when playing on Batteries

Thread Starter


Joined Jul 19, 2018
I've got this radio which plays perfectly fine when powered from AC.
But when powered from batteries it usually plays fine for a while and then starts making these noises:

(I'm not turning any knobs or pushing buttons, just leaving it on. It makes these noises on all stations, regardless of where I turn the frequency knob)

It's not as loud on batteries as when powered from AC with the knob set to the same loudness, too.
It takes 4 AA batteries.

This radio belongs to an old grandpa.
He wasn't using it in the winter and it seems the radio was left sitting outside in the cold (up to minus 15 - minus 20 C) for a few months. It wasn't sitting in the rain, though.

One battery contact on the radio (the one where the positive of one battery is connected to) wasn't making a good contact, so I melted a bit of solder on it to 'restore' its conductivity. This is the only flaw I could find.

So, anyone got any idea on why it's behaving like this?


Joined Aug 21, 2008
Sitting outside in the cold could have damaged a power bypass capacitor, which can be the cause if the squegging in Radio Noise 2.

Look for swollen or leaky electrolytic capacitors or just put a large electrolytic (discharge first) across the output of the battery pack for a quick check.