Gusfmm wrote:As a Materials Engineer myself, I'm initially quite puzzled by your description and that picture. As much as I'd like to throw in an initial guess, intrigue makes me strongly feel I need to be back home to look at my Oasys' sliders first. The little yellow-gooish residue in the white painted middle slot is indeed weird; I guess how it got there first and foremost. You sure you've confidently eliminated all possibilities of somebody else sneaking into your studio and meddling with your Oasys? (wait, I said I wasn't gonna guess yet...)
The picture may be a little misleading, since it's a close-up, and the camera flash really accentuates the residue color and texture.
So here's what transpired. Initially, the slider cap was "extremely" sticky to the touch. So sticky that my finger adhered to it momentarily. On a tacky scale of 1-10, where 10 is "super-glue" and 1 is "not sticky at all", I'd say it was about a 5 or 6. I inspected the remaining caps, and removed the biggest offender. Remembering my experience from the Blueberry cable I mentioned in my first post, I took the cap to the sink and washed it with a mild soap and warm water mixture, and saw that some of the gooey substance was starting to break up. With my fingernail, I started to scrape some of the goo off the surface (you can see this most clearly on the near side -- there's a line that goes across the entire side). Then I snapped the picture and posted here.
After doing some research, searching for "rubber coating deterioration", I found several interesting discussion topics describing a similar phenomenon with camera and gun parts, binocular housing, and most prevalently, interior surfaces of VW and Ferrari automobiles, along with several courses of action to combat or solve the problem.
Since then, I've soaked the pictured cap in an isopropyl alcohol bath, which has removed about 90% of the rubber coating, and have one cap that is now shiny black plastic, as opposed to the default matte "rubberized" finish on the remaining knobs and sliders. I have removed all the caps from my Oasys and upon closer inspection have found nearly all of them -- including the rotary knobs -- slightly tacky.
I have submitted an inquiry to Korg USA concerning replacement parts, and am also asking for a quote from Selco to see if I can get some compatible parts that come in nifty new colors. I'm still awaiting replies.
In the meantime, I've been experimenting with whatever other knobs that also have a 6mm "D"-style shaft that are available in my studio. The control knobs for the padKONTROL look kind of nifty, although they are wide enough to obscure the LED ring (and I've only got 2!). I also tried one of my Prophet'08 knobs, and that looked interesting too, but I think until new, non-sticky ones arrive, I will pull a few off the MS-20 Controller which isn't hooked up at the moment. I don't have anything on hand to try out for new sliders at the moment.
