Hi D A Franzon,
Welcome to the forum.
Unfortunately, I agree, this sounds like a software problem. Have you tried to contact SoundCraft? They are a holding of Harmon International and still have offices located in the UK. In fact, Harmon is planning on moving the entire Studer facility there.
I would love to help you but I'm afraid that a 24 track, 2", software driven machine of that type is over the heads of most of the residents of this particular forum.
You may have better luck with your query on one of the professional forums devoted to magnetic tape recorders such as the Ampex List. I've seen mention of these machines there before and there is a great depth of knowledge about a great number of machines that can be discussed there.
The Ampex list is a list serve style forum. You can subscribe to it here;
http://recordist.com/ampex/ BTW If you have a moment, I'd love to hear a little about this machine which may have been one of the very last large multi-track magnetic tape recorders produced. Do you see very many of these machines in use?