Another quick note on RY-5500 noise: I recently received an e-mail that described a subtle "clicking" noise emanating from the RY-5500 when under various thread or belt tensions. I noticed this too from day one of ownership and thought it might be normal. When the major noise occurred and I fixed it as described in my article, I noticed this clicking also went away! I can only suspect that sound is abnormal, too. The good news is it is possible to have a completely silent RY-5500.
Kip
Kip