Abnormal Hissing Sound

[benbol]

Hi Everyone,
I am new to this forum, but not to korg synthsizers. Could anyone please help me out? When I first switch on my 01Wfd, it makes an abnormal hissing sound. It works fine if I switch it off and on again. Sometimes I have to do that twice. Any help will be highly appreciated.
Warm Regards,
benbol

[T3owner]

The 01/W has a history of electrolytic capacitors failing.

This should provide some insight:
http://hajo.kessener.net/electronics/ko ... nd-repair/

[jhulk]

sounds like ripple in the psu check the ripple with a scope if its to high

with the service manual recommendation for max ripple change the filter caps

[benbol]

Thanks so much for this link. It will be useful indeed.
Ben