Why is it obvious? Is it sticking, not moving, cracked or stripped spring metal?
Maybe a picture of the offending bit or section of the unit may help.
With a picture to look at, many of us with a De Vere free standing enlarger may be able to look at their machine to see any obvious difference.
From memory, and I mean about 30 odd years ago, the springs do crack and/or tear and are a bit of a bitch to replace if you do things the wrong way.
Where in the world are you? You never know just who is possibly next door.