This is what I would do:
- Where did you buy it?
- Who else sells it?
Connect with vendors that resell the duplicator, and them see what any of them may know. In the disc media fields, things are a bit more "clued in" on the vendor side. Linkyo, for example, has employees that know quite a bit about blank media, burners, duplicators, etc. (Linkyo owns
Supermediastore.com. Not sure if they ever sold this specific product, however.)
I've come across quite a bit of good information that way, in past years.
That's also VERY crappy that Vinpower is unwilling to repair, or assist in a repair, of their products. They can't stand behind their own products? That's really quite unacceptable. If there are competing products, for this exact sort of duplication need you have, I'd go that route for any future purchases. (I'd need to know more about your exact needs, before putting forward any kind of suggestion.)
If Vinpower never released documentation for these machines, and third parties are not allowed to repair them, then it's unlikely that any schematic documentation is out there, in the wild.
A last-ditch attempt may be for patent documents. If this is a unique product, and is patented, many times patents have detailed plans. Few people realize what those free government documents have stored in them!