Which one do you have (the pictures are links):
The first one looks an awful lot like a rebranded Viewsonic Airpanel 100. If you have that one, then you're in luck becuase I have spare power supplies. They're 19V 3.16A 60W, so they might not be compatible. Can you check the voltage again?
The upside is that once you find a power supply there is a whole lot of software you can run on it:
https://www.mobileread.com/forums/showthread.php?t=32551