Converter update:
The ebay seller gave me a prompt refund on the non-working PD converter. I happy there was no hassle.
She didn't ask me to send it back, either. I called PD and asked them if it might be an easy fix I could do or get a friend to. They said no, but surprised me by saying they have a program whereby I send in the unit, and if they can fix it they do so for $110, with warranty.
That sounds pretty good -- for the price of postage, I get a chance at getting a converter for not much more than my original $100 I spent at ebay. And if unfixable, they just recycle it.