I have a 128D which died (due to an LtK upgrade gone wrong). I replaced the affected 74Ls08PC IC (u3) and it seemed to work again. As I understand it this chip is responsible for memory bank control. Well it's still acting flaky with the IEC bus, and I presume it's due to this chip mishandling the serial to RAM calls.... I'm going to pull it and resolder my socket and try again but would like a main board as a backup. So anyone have a 128D with a dead drive, I'm your guy! :)