Dave, thanks for the advise on using the IO-trace, it helped me see what was going on on the bus.
A little update, it turns out that there is a problem with GPIB on my A60 board which was causing this. It, as far as I can see, works otherwise. If someone has a spare that they are willing to sell for a fair price please contact me offline, its part no. is 08340-60299.
Regards
Saevar
