Korg DW8000, Mono/Poly, MS-20...

I have a DW8000 with Angel City turbo mod. When I play live, the DW  will get a "stuck note" that keeps sustaining when I play. It doesn't
happen all the time, but it's a bit frustrating when I play a gig. I  usually turn the volume down and change a program, then change back  to stop the "stuck note".  It happens in poly and mono modes. I mostly use   organ, e-piano and lead synth patches, but other patches are affected as well.  Anyone know what's causing this and a way to "fix" it. Thanks.

Steel

Hi Guys,
Sorry for the off topic post , but this is about a keyboard so rare
that I wanted my list partners on all my keyboard lists to have a
chance to see this and maybe buy it if they are interested. I have
decided to sell my Rhodes Mark V electric piano. It is the best
Rhodes model ever produced and only 2000 - 4000 of these were ever made
before the Rhodes factory shut it's doors forever. It is one of the
rarest keyboards on the planet. I just listed it on eBay for an opening
bid of 3.00 U.S. and the addy for it is at
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ih=016&sspagename=STRK%
3AMESE%3AIT&viewitem=&item=260085588327&rd=1&rd=1

Thanks for the list and sorry again for the off topic post. frank