I can find no reason for that ROM to be in there. As far as I know, its not needed for the upgrade card.

So keep it as basic as you can to see if you can get it going. By the way, I never heard of a TAM yet with bad caps. That is not saying they do not exist, they are rare machines, but I have yet to hear about one needing a re-cap. Mine works fine with no re-cap. Although I want to get it done. So I think maybe your issue is more with corrosion than anything. Which is not bad news since you can cob together a replacement board.