Amiga 600 sound distorted?

[Stedy]

Check C303 and C304, I had to replace these on my A600. They provide bulk decoupling for the LF347/TL084 audio filters. Also check C324 and C334, they are all 22uF electrolytics. I used an LCR meter to check the caps were duff, though one smelt funny!

Mine had a 'black goo' spot on them.

Does the -12V of your PSU still work?

[Stedy]

@TjLaZer

Not easily.

You can use the resistance function of a multimeter to ascertain if the capacitor can hold a charge. All tests are done with the power off.

You may be able to test the capacitor whilst still on the PCB.  Use a high range resistance function of a DVM (100K or more) and connect the probes across the capacitor. The reading should quickly rise. If the resistance does not rise, the capacitor is suspect.

After testing the capacitor, use a 1K resistor or similar to short it out, before testing the next one.

I have paraphrased things somewhat, but I hope you get the idea.