Hi,
I have a Korg SDD-1000 vintage delay that stop working properly. Delay is ok, BUT
the output signal is not clean, you can hear the modulation oscillator clearly and very loudly.
I think capacitors need to be replaced, but which ones?
Thanks for your help.
No help? I still haven’t solved the problem.
I agree that it is most likely an electrolytic capacitor. However, I don’t have the schematic and it doesn’t appear to be available on the internet so I can’t point you to any particular capacitors. I’d recommend using an ESR meter to test all of the electrolytic capacitors while they are still installed on the PCB. Also look for any capacitors that are bulging or leaking.
If you don’t have an ESR meter and don’t want to get one then the other option would be to test them out of circuit. You would desolder them one at a time and then measure their capacitance with a multimeter or capacitance meter to verify they are still the correct value. If you don’t have a capacitance meter you can measure their resistance instead. For a healthy capacitor resistance will start near 0 then rise towards infinite. These tests do not work while the capacitor is installed on the PCB.
More info about testing capacitors here