Hi all, My name is Tony, I just build a darkroom with some friend. We have no experience and heaps of question! We bought a Durst AC800 enlarger and it came dismantled. the counterweight spring at the back of the column was as well apart. I put everything back together but can t figure out how to put the counterweight spring. As a result i cant simply use the grip to move the head up and down. I can t find anything on internet about it. Thanks!