Ah, the joys of upgrading! Thanks very much for the information. I guess I'll be sifting through ebay looking for some good deals on stuff.
I pulled it out of storage last night and tried a couple of games. (Test Drive, Road Warrior, Off-Road Challenge). They worked! And the machine fired right up. (I'll check the batter tonight) However, about 30 minutes after using it, the video just went out. I plugged into the RCA mono video out and it worked, so I'm wondering what happened. I'll play with it later.

Turns out I have Workbench 2.0 but I'm sure that's not a huge leap over WB 1.3 I've done no upgrading on this box since I bought it back in 1986(?).
Peace!
Sebes