hmm, thanks for that.
i was really hopeful, but it still doesn't solve the problem.
I was wondering if its worth getting hold of a max7221, perhaps they are more robust against EM interference?
I have currently testing with two separate rows of 5 digits (each with their own pic). there is definately some kind of current flow problem as when one come on, the other will die etc.

the other post, is interesting as the problem is very similar. However, i have already put the two capacitors between the 5v and the gnd . Any harm in increasing the values?
further thoughts, always welcome