[Mondial]

Yes, you can use the oscilloscope as a signal tracer to find problems in the audio circuitry. Here are a few ideas.

If you are uncertain of the voltage level at a point you are testing, make sure the attenuator of the scope is at the 1/100 setting and AC coupled. This will prevent damage to the scope and overload. If you do not see the signal, you can reduce the attenuation to 1/10. 

Start at the detector output ( top end of volume control ) and look at the signal from a signal generator modulated with a sine wave tone. You should see an undistorted sine wave there. Then go to the output of the first audio stage and you should see the same waveform only larger when the volume control is advanced. Proceed stage by stage until the output. If at any point the sine wave becomes distorted, then concentrate on that circuitry as the cause of the problem.

You can also see the level of hum on the power supply with the scope. Just make sure it is AC coupled an use the 1/100 attenuator setting.

Once you learn how to use it, the oscilloscope becomes a very valuable tool in signal tracing and troubleshooting.