I bought my Turbo Grafx-16 when it was $100 and came with a bad tshirt and
football. NEC sold a device which took the place of the back cover and
conneected to the I believe 75 position 0.1" spaced connector that "added"
"features" such a composite video and stereo outputs.

It was very obvious that this $50 or so box was just a bunch of connectors.
I took an oscilloscope, stereo and composite computer monitor to the back
connector one day. I found componenet video and each color as well, left and
right audio as well as a few other fun but useless signals. I rigged an ugly
mess of wires onto the back of my TG-16 and enjoyed clear unmodulated video
as well as stereo.

I was at the Consumer Electronics Show in Chicago the first year NEC
Technologies was there with the TG-16 as well. They had several games stored
on boards that hung out of the game system and were populated with EPROMS. 
HuCARDS are just memory - they have no weird logic as inside Nintendo
cartridges. There was also a very homemade looking card that conected a
TG-16 to the parallel port on a Mac!. Some games they did not even bother to
burn into EPROM for the show. There was an engineer there who probably made
that board as she knew everything about it. I would like to meet this fellow
again. There were a few Xilinx chips on this board and it was not green
screened either. The next year NEC Technologies had a normal booth that was
well, quite boring.

I'll post the pinouts if I locate them again. The TG-16 is still my favorite
home game system. I'll but any HuCards if you have them as well.

02-20-2000