Roland W30 Distorted Sound

[pp10050]

Hi, I bought a Roland W30 Workstation fairly cheap last week. Apart from the usual problems with the disc drive ( which I've sorted) I have a problem with the sound out of the "Mix" socket being very loud and distorted. Turning down the vol. level on the patch has no effect. also even with the main volume turned to almost off, I can still hear that the sound is clipped and distorted. It is like this with all the patches I have loaded, both the Roland Samples and 3rd party ones. I have the SM for this unit, before I start to delve into the Analog board or the DAC chip, has anyone come across this before?

Thanks, Paul