I found some bad bits, but it doesn't change anything with the emulation. Plus1 locks up rightaway whether these bits are changed or not. I will look into it again when we get the Mattel games playable(these run on the same COP400 model)
I see 2897,17 and 2844,17 are the bits under a smudge, and 1673,2067 has dirt or damage to the bit. But 687,1325 looks OK (0 bit) and 875,17 looks OK (1 bit).
I'm pretty sure about the 3 "maybe" bits- take a look at the space below those bits; you can see a faint line, the same as under other 1 bits that have zeroes below them. Unfortunately, I lost the Plus One die, but I do have a top metal pic. The top smudge is there, too, so you can't directly see 2798,17 and 2844,17, but 1673,2067 looks good.