Interesting Heathkit Expansion Board

I just pulled a really interesting-looking expansion board from a dead Heathkit H-89 I acquired a few months ago, and I was wondering if anyone knew anything about it, and/or had documentation and software to support it. And I know is what I can see; can't find anything on 'net. It's an N.O.G.D.S. (New Orleans General Data Services) HA-89-3-B. This thing is a whopper, the only thing it doesn't seem to have on it is another CPU. It has: * AY-3-8910 sound chip; * SC-01-A voice processor chip; * ADC0809 (there are four ports marked JOY1-4 on the board, so I'm assuming joystick pots); * 8253 Timer chip (some of its outputs extended to a 10-pin header); * 8259 Programmable Interrupt Controller; * TMS9918 video display processor and supporting RAM (there's cable running off the board that terminates in a RCA jack), for a second video display apparently; * AM9511 math coprocessor; * a couple of PALs and the usual array of buffers and decoders. So for all things, this looks like it was meant to support some really interesting applications on the H-89, maybe drawing/CAD, etc. (but the sound and voice chips?). The machine it came in also had a battery-backed real-time clock expansion board (with AA battery that leaked down onto the flyback transformer, yuck), and a parallel port board. I'd love to play with this thing, but I thought I'd ask before I spent hours following traces... --Patrick