Korg Poly800/EX800 Users

I have a Poly 800 here with a problem;..hope someone here can point me in the right direction!

Problem is that there is a constant noise when no note is being played. When a note is being played the noise disappears and stays away until the filter envelope is closed. Meaning when the filter envelope is longer than the amp envelope the noise only reappears when the filter envelope closes. I think i may have narrowed it down (with my basic understanding of electronics) to the 2SK381 fet that acts as a noise gate as this is being triggered after the closing of the filter envelope. Could this assumption be correct or has anyone else had a similar problem? Thank you for any answers, i would like to get it back to normal as it's a great little machine...

Tom

All eight envelopes need to close before the noise gate shuts of the audio path. You're right that the 2SK381 FET is the noise gate. But, since the noise occurs when the gate is blocking, I would say the problem is downstream of the FET and probably not the FET itself.

The noise is not continous as in white noise for example but is 'fluctuating' as if the audio path is 'polluted' if that's any help...

Meanwhile i'll just check everything with my dmm...