WTD: help debugging an eprom emulator

Hi, Sorry for clogging up classiccmp with this message, but it is sort-of classiccmp related (I wanted to build an EPROM emulator to make ROM development on my BBC Micro a little faster). I've been trying to get my EPROM emulator design to work - I can't see any errors in the wiring and AFAICT all the ICs are fine. I've uploaded the schematic to <http://www.philpem.me.uk/epemsch.png>. If anyone spots a design error, please let me know - I've gone over the schematic a few dozen times and I'm almost at the point of giving up :-/ It looks like data is getting loaded, but isn't getting output to the target device properly... %DEITY knows why, though... Thanks. -- Phil. | Acorn Risc PC600 Mk3, SA202, 64MB, 6GB, philpem(a)dsl.pipex.com | ViewFinder, 10BaseT Ethernet, 2-slice, http://www.philpem.dsl.pipex.com/ | 48xCD, ARCINv6c IDE, SCSI ... Psychoceramics: The study of crackpots.