> I think the 561 and similar can have termination on them but it's done 
by
> actually inserting resistor packs. There should be two single row 
sockets on
> the top back edge of a dozen or so pins each. These each take a
> resistor pack.

Thanks for everyone's help on this.

The problem was, as suggested, lack of termination on the CD ROM drive.
Having a closer look at the drive there are row sockets for resistor 
packs
on the top of the drive - however, they are aligned in the same plane as 
the
top of the unit, so its not immediately obvious what they are (well, it 
wasn't
to me!)

Managed to snaffle some resistor packs off an old CD ROM drive.

Still had problems booting from the CD ROM drive (this may be because
I setup the swap space incorrectly?), but things went okay when I used
the inst-12.fs image on a floppy disk.

Sets all installed okay, any I no have the fun task of trying to setup a 
workable system :-)

Many thanks,

Jason
--
     Jason O'Broin - Senior Development Engineer, ATM Adapter Group
Madge Networks, Sefton Park, Bells Hill, Stoke Poges, Slough SL2 4JS. UK
Phone +44 1753 661258 Email: jobroin@madge.com or jobroin@dev.madge.com
 - Multi-meeja: Punjabi word, meaning 'Technology with no apparent 
purpose'  -