Tore into the 2nd PPNG I got on ebay:
The mainboard is different from what is in mine and John's, and the lcd is also different. The touchscreen and LDC cables are reversed, which leads me to beleive that someone put a TSU3K screen assembly and mainboard into a PPNG case (well, they TRIED to), and box. I did a search for the screen p/n and only two returns from google. One was a remote central post about a broken TSU3K glasstop, and the other led me to some LCD discussion forum where the same person posted. When I connect a battery to the unknown board, it beeps twice, then a second later a HIGH-PITCHED squeal can be heard. After it sits for a few minutes, the squeal stops. If I press a hard button, it comes back. Obviously something to do with the backlight controller. That mainboard also will not talk to my laptop.

This test is leading me to believe that possibly only ONE pronto USB device may be installed on a given PC?