That's very difficult to answer. If it is a computer board, it could be quite expensive IF it can be repaired.

There is a Yahoo user group called 430_440_630_640_730 (or even some other Bernina user groups that may be more applicable) may be able to help. You will need a Yahoo email account, search Yahoo groups for the Bernina groups, ask to become a member, and once you are, you will have access to all the past conversations, files, projects, etc., as well as being able to post your own question to a very knowledgeable group of Bernina users. There have been many discussions such as yours.