Christine-,
Your comment about not using grease on the gears brings up another question I've had. On our 4622A and 3810, (both machines never been opened until we got them), and our 538 and 518, there is an amber to light brown grease on all the plastic gears. By the feel of it, it's very old. The grease is almost a wax consistency from it's age.
OK, If I am correct this is factory grease on the plastic - nylon gears. But most people say to use no grease. I'm curious if maybe the factory used a special grease not available to the general public which is why other greases cause the gears to deteriorate.
Joe