Try contacting the Samsung Parts department at 800-627-4368 or by trying the www.samsungparts.com website.
I think this is your part here:
And here are all the parts available for your model:
Does that help?
Gremlins made off with my wireless speaker card. No idea how this happened, but I now have no surround sound. Anyone out there know if there's a way to get a replacement card?