This is a stupid mistake. On connecting a Disk II drive to the interface card I managed to get the plug on with only one row of pins on the connector. I powered up the Apple but immediately noticed somthing wrong so switched off!
Now the drive spins up on power up but does not boot a disk. I have tried another drive and that is fine so it is not the interface card.
Is there a fix for this?
Any information gratefuly received.