I have a suprima 40 with exactly the same problem, I have an engineering background and resoldered some of the components on the main circuit board last time this happened and it fixed the problem for 3 years - now the problem has re-occured - not happy, will never buy a potterton again!
My answer therefore is they should be able to fix the problem as opposed to making you buy a new board. the repair should take no more than 30 mins. Looks to me like potterton are profiting by our misfortune and a cr*ppy product.
damien
May 2007