Thanks Zip -
I had a look under mine, too, and didn't see anything. I've got an email in to the manufacturer on this a well, but they are slow to answer. I don't mind so much replacing the amp as long as I can verify it as the solution to the problem before I spend the money.
I'll wait a little longer for some other feedback and go from there.
Thanks for your efforts - this is a great forum.
John