Diagnosing Vintage Radios With No Sound

Video Transcript

"Hi I'm Larin Parker with Expert Village and we're looking at the back of this radio to talk about what you can do to diagnose problems if you're not getting any sound out at all. This is a little bit trickier and in many cases you're probably going to want to consult with an expert. One trick is just taking your battery powered speaker and using it as a signal tracer, let's say that the speaker was disconnected in this unit. The speaker could be disconnected but all signals leading up to the speaker could be fine and we wouldn't know it unless we hooked up another speaker. Generally speaking it's safer to work on battery powered stuff while it's on. If it plugs into the wall, you just want to of course (We will have to pretend because we do have a speaker working on here). I can also tap certain parts of the circuit at intermittent points and kind of listen to see if I can find tones. Here I'm getting little intermittent things, here's kind of a buzz that I'm getting. At least that tells me that I'm getting energy through there. What I look for of course is going to be the audio signal. Usually the secret to that is you start with the connections to your speaker and you sort of work your way back. If it's not reaching the speaker, you find the speaker then you work back component by component trying to see where the sound ends and then you find your wire isn't connected. All I have to do is I take this radio shack amplifier and I'm doing circuit sniffing here or signal tracing and I just have hooked up to the sleeve I have this hooked up to the negative terminal or to ground and I know that's this side of my D cell batteries the flat side of the D cell batteries. If you're looking at a circuit board and you want to find out where a ground is, generally speaking ground is going to be the biggest, fattest trace on there, whereas most traces going through the circuit board connecting things they?re going to be thin little wires. The big fill, the big fat one is going to be ground. You can reference to that, remember when you're hooking up live circuits to anything, you just want to use one hand, so what I do is I clip this to ground and then I go in and probe other parts of the circuitry to find out what's going on. That's one way to trace a problem and actually hear where the audio signal ends before it reaches the speaker. Then you can reconnect the dots and hopefully get things restored."