The ribbon cables hardly ever go by themselves, in other words just crack or break. The copper typically peels away when you remove them and try to push them back in. So if no one has opened the radio and messed with the cables then I doubt the cables are the problem.
The Driver board has more that likely been burnt out, you can replace it but it's a bit of work. Experienced repair person will avoid pulling those two front cables and get the job done, but it's tricky. If your doing it your self I suggest that you make sure Icom has the driver board in stock and also just pick up two new cables.
73s
Rob