I might be wrong about the Star Opal having a 6301 processor. As I say, it is the same black blob format found in current generation Novag products as well as Excalibur products. The only visual differences are the number of connecting pins.

The older Opal Plus (or Opal II, can't recall which one but I think it is the Opal Plus) definitely had a 6301Y processor inside. I remember opening the older model up to check this. The processor was the same as found in the much older Mephisto Europa or Saitek Express 16K / Cavalier. Definitely a 6301Y. As Robert says, the 6301 is single chip anyway, so I would not expect to find an EPROM in a single chip machine.

Novag of course claims that the newer Star Opal is slightly stronger than the older Opal Plus. Since I am almost certain that Novag have not changed the actual program itself, perhaps the slight increase in playing strength came from having a different processor - the mysterious black blob.

That said, I am not really sure there is any increase in strength as Novag claims. As I mentioned earlier, match results against other computers are very inconsistent with this 16K Novag program. I think it has a lot to do with the inbuilt randomisation of this program. It would probably play a lot better if it just played the "best move" from it's perspective each time.