The larger 20 pin one nearest the ROM sockets (SN74LS245N)
The Minerva error codes, since fitting the logic IC & IC8, are the same every time I switch on and I don't get the black & white lines any more
I did piggyback the other 2 logic IC's as my theory was that if one of the onboard logic IC's were faulty the combination of a piggybacked logic IC would cause random things to occur, but everything remained consistent which suggested to me the onboard and piggyback were working identically. But I know nothing about this so that is very much pseudo science!
Thanks
Tony