Anthony, you are one generous and great guy! I appreciate the offer to loan me your modified 4288. So, did you soldered in a 28-pin socket? I have seen a thread in which Dave W describes that procedure and I am going to do the same. It just doesn't make sense to keep messing around with the 24-pin PROMs which are getting "harder than hen's teeth to find". I will wait for the chip you burn before doing "open-heart" surgery on my 7747. Thanks again.