I found a handy source for a replacement TI firewire chip used in the FF400 , regular sources long since having been exhausted .
Its a popular brand of firewire pci card which can be found very cheaply now , as it happened I found one for sale locally for 10 euros , so thats very handy to have .
I was able to get some backround info on the non working FF400 I bought from the seller ,
He bought it around 2010 , used it for around 5 years ,then it was left on the shelf for ages ,
when he tried it again in recent times it was no longer detected by the computer .
Ive scraped every post I could see on the internet relating to the FF400 , with some very useful contributions from our old friend Cyrano on the RME forum,
He also dissappeared from Groupdiy around the same time as me ,although his account still exists , he no longer posts there .