Had exactly the same problem with my MPU327 ( Williams Rottendog MPUI/Driver Combo ) board.
Check this thread if youré interested.
http://aussiepinball.com/index.php?topic=5348.15I got my 74hct240n from a guy up the road, his website is listed in that thread too.
I did go and have a look for a chip for you but cant find them. If Homepin cant find one for you get back to me and I'll have a better look.
But changing it yourself is way quicker and cheaper than sending it back to Rottendog.
