I've been having exactly the same experience as TexMark and was brave enough to take the thing apart and attempt the cleaning of the ribbon. I've searched quite a lot on the Internet for part# 5765M471-60
with no success.
I hate the idea of trashing a perfectly fine 5 year old oven and I've been cooking fairly successfully with "Keep Warm+0"=170, "Bake+0"=350 and "500" for the whole winter, but as spring comes around and we start to think of baking and tackling those finer recipes I'm finally going to have to suck it up and buy another oven that doesn't match our stove.
Are there any last words of wisdom that might help me avoid defeat to the planned obsolescence?