Global 3900DD sewing machine

I am selling this industrial sewing machine because I am moving. It is a very very good machine. I have used it for many years. Unfortunately it needs fixing. Once fixed it’s perfect again. I am not sure of the problem. I bought it a few years ago for around 700€ from Andrevo in Haarlem. They can also fix the problem. The fixing will cost around 100€ for them to come out.