Bigboard II, odd laptop

Anybody out there familiar with the Bigboard II? I have one, and rather like some features of the thing. One of the features in the rom code is that it'll look at the second rom socket and try some sort of weird CRC algorithm on it and if that checks out transfer control to the chip. Problem is, I don't understand the code. Also, somewhere I have this 286-based Zenith "laptop", non-functional the last time I tried it. Anybody know if there's any service info out there on this thing? I used to be a ZDS service center way back when, but we stopped doing that when they moved all of the training to Chicago and required several trips a year plus _paying_ for the training to continue with it (more than we made working on their stuff), and so I never saw any service data on that sort of thing, though I do have some on their earlier stuff, and monitors, if anybody needs some. I do remember seeing one of those in operation one time, and it had a real pretty blue-lit screen. :-) -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, a critter that can be killed but can't be tamed. --Robert A. Heinlein, "The Puppet Masters" - Information is more dangerous than cannon to a society ruled by lies. --James M Dakin