Besides being inspected, cleaned, oiled and greased, the upper and lower tensions have been adjusted and the bobbin cover plate re-attached. There was nothing mechanically wrong with this machine. Get this - the shop visit was more expensive than the purchase price of the machine! I could have skipped the visit and spent the money on accessories instead. Still, no regrets as it has received the blessing of the service technician.
If I want the 403A to make decorative stitches, it will need more cams. It should have a zipper foot and a few others. Maybe a carrying case, too. A case would make it easier to transport - this thing is heavy!
The machine is supposed to have a bottom cover. It is missing. Performance is not affected by not having a bottom cover, but having one keeps any oil drops from damaging the table below. So, if I can find one, and it is reasonably priced, I will get it.
Even without the bottom cover plate and the extra accessories, this supasses my expectations for a sturdy back-up machine. I now understand how people become obsessed with old sewing machines.
It needs to be taken on a test drive. What should the first project be?